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Micro‐mechanical resonators are building blocks of a variety of applications in basic science and consumer electronics. This device technology is mainly based on well‐established and reproducible silicon‐based fabrication processes with outstanding performances in term of mechanical Q‐factor and sensitivity to external perturbations. Broadening the functionalities of micro‐electro‐mechanical systems (MEMS) by the integration of functional materials is a key step for both applied and fundamental science. However, combining functional materials with silicon‐based devices is challenging. An alternative approach is directly fabricating MEMS based on compounds inherently showing non‐trivial functional properties, such as transition metal oxides. Here, a full‐oxide approach is reported, where a high‐Tc$\rm {T_c}$ superconductor YBa2Cu3O7 (YBCO) is integrated with high Q‐factor micro‐bridge resonators made of single‐crystal LaAlO3 (LAO) thin films. LAO resonators are tensile strained, with a stress of about 350 MPa, show a Q‐factor above 200k, and have low roughness. YBCO overlayers are grown ex situ by pulsed laser deposition and YBCO/LAO bridges show zero resistance below 78 K and mechanical properties similar to those of bare LAO resonators. These results open new possibilities toward the development of advanced transducers, such as bolometers or magnetic field detectors, as well as experiments in solid state physics, material science, and quantum opto‐mechanics. [ABSTRACT FROM AUTHOR]

Mixed‐conducting perovskites are workhorse electrochemically active materials, but typical high‐temperature processing compromises their catalytic activity and chemo‐mechanical integrity. Low‐temperature pulsed laser deposition of amorphous films plus mild thermal annealing is an emerging route to form homogeneous mixed conductors with exceptional catalytic activity, but little is known about the evolution of the oxide‐ion transport and transference numbers during crystallization. Here the coupled evolution of ionic and electronic transport behavior and structure in room‐temperature‐grown amorphous (La,Sr)(Ga,Fe)O3‐x films as they crystallize is explored. In situ ac‐impedance spectroscopy with and without blocking electrodes, simultaneous capturingsynchrotron‐grazing‐incidence X‐ray diffraction, dc polarization, transmission electron microscopy, and molecular dynamics simulations are combined to evaluate isothermal and non‐isothermal crystallization effects and the role of grain boundaries on transference numbers. Ionic conductivity increases by ≈2 orders of magnitude during crystallization, with even larger increases in electronic conductivity. Consequently, as crystallinity increases, LSGF transitions from a predominantly ionic conductor to a predominantly electronic conductor. The roles of evolving lattice structural order, microstructure, and defect chemistry are examined. Grain boundaries appear relatively nonblocking electronically but significantly blocking ionically. The results demonstrate that ionic transference numbers can be tailored over a wide range by tuning crystallinity and microstructure without having to change the cation composition. [ABSTRACT FROM AUTHOR]

We report the presence of electron-spin-phonon interactions in half-metallic ferromagnetic Sr2FeMoO6 (SFMO) double perovskite thin films using temperature-dependent Raman spectroscopy. A series of SFMO thin films have been prepared on LaAlO3 (001) single-crystal substrate using the Pulsed Laser Deposition technique. These depositions have been made in different gas-conditions such as in vacuum, and under nitrogen and oxygen gas pressures. At room temperature, Raman spectra manifest a Fano feature which indicates the presence of electron-phonon coupling in the films. The electron-phonon coupling strength further changes with a change in deposition conditions. Magnetization results show that the SFMO film grown in vacuum has the highest saturation magnetization which suggests better cation ordering as compared to the other films. For enhanced understanding, Raman spectra were recorded at varied temperatures and the data were analyzed by theoretical model fittings. A parameter quantifying temperature-dependent anharmonic nature of phonons has been derived using Balkanski model fits. This parameter shows a drastic deviation in the vicinity of Curie temperatures, manifesting a spin-phonon coupling in SFMO films. We further show that the spin-phonon coupling strengthens with improved Fe–Mo ordering. Any experimental observation of spin-phonon coupling has not been reported for SFMO systems till date. The magnetization data corroborate well with these observations made by Raman measurements. Our results of Raman spectroscopy, magnetization and resistivity collectively suggest that the SFMO films exhibit electron-spin-phonon interactions, which are influenced by the cation ordering. We also devised out the method of relating the anharmonic nature of Raman modes with the degree of Fe–Mo ordering and spin-phonon coupling in double-perovskite materials. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) material plays a crucial role in determining the device efficiency and stability of organic solar cells (OSCs). Tin oxide (SnO2) semiconductor is commonly used as ETL in organic solar cells and recently has attracted significant attention. In this paper SnO2 particles deposited by pulsed laser deposition (PLD) are used as ETL layer in inverted organic solar cells with structure (FTO/SnO2/PTB7-Th:O-IDTBR/ MoO3/Ag). The characterizations of cell using the Ossila Solar Cell I-V Test System have been investigated as well as the structural properties of SnO2 thin film using a Field emission scanning electron microscope (FESEM), The atomic force microscopy (AFM) and X-ray spectrum have been also investigated. It has been found that the Power conversion efficiency (PCE) of solar cell is 15.08 %. The stability was measured for 30 min with continuous illumination under the ambient air conditions, it was decreasing gradually over the illumination period to about half initial value of efficiency. The FESEM images and XRD spectrum show that the films were crystalline. The XRD spectrum shows the presence of several peaks belonging to SnO2 nanoparticles. The optical properties of SnO2 film indicate the increase in the transmittance and refractive index spectrum, while the absorbance spectrum decreases, the maximum absorbance was observed at 320 nm wavelength and the optical energy gap record about 3.1 eV and the grain size for SnO2 reported around 20–60 nm. [ABSTRACT FROM AUTHOR]

This work is concerned with the synthesis of two types of composites thin films (Sb2O3:WO3 and (Sb2O3:In2O3) with different concentrations (0.0,0.05,0.1, and 0.15). The prepared thin films are characterized with the use of the X-ray diffraction atomic force microscope AFM and UV-Vis–infrared spectrophotometer. The structural examination shows that both composite's thin films were polycrystalline with nano size with cubic phase as majority and orthorhombic phase as minority phase. The crystal size decreases from 34.6 to 24.7 and 21.7 nm for (Sb2O3:WO3) and (Sb2O3:In2O3) thin films, respectively. The average roughness shows nonregular growth by increasing the concentration of both oxides. The optical energy band gap shows a red shift for both types of nanostructure thin films, which populate these composited thin films for solar cell applications. [ABSTRACT FROM AUTHOR]

We present a systematic investigation of the detailed structural, optical and magnetic properties of ZnO thin films deposited by pulsed laser deposition as a function of varying Al doping from 0% to 5%. The observed features can be associated with strain introduced into the ZnO lattice by the incorporation of Al. Enhanced optical transmittance values close to 95% were achieved in Al-doped ZnO epitaxial films deposited on sapphire substrates. In addition, these films exhibit robust ferromagnetic properties at room temperature with saturation magnetization that varies from 143 to 63 emu/cm3 for Al dopant concentrations from 0% to 5%. It is demonstrated that the saturation magnetization is related to the strain introduced into the lattice with increased Al doping. [ABSTRACT FROM AUTHOR]

This research is devoted to the fabrication of zinc selenide nanostructures using the pulsed laser deposition (PLD) technique in a vacuum under a pressure of 2. 5 × 1 0 − 2 mbar. The structure and structural properties were studied, as it was observed that it had polycrystalline structures and showed peaks for zinc and selenium and peaks belonging to the compound zinc selenide. As for the morphological characteristics of the nanostructures, the structures showed the nature of the surface and the roughness to identify its surface properties. Photocatalysis was carried out using several techniques (visible light, ultraviolet radiation and cold plasma), where a plasma jet system produced under normal atmospheric pressure was used in the treatment, with an exposure time of 4 min and an argon gas flow rate of 3 l/min. The hydrophilic properties were studied to apply these compositions in the self-cleaning process and photocatalytic activity. The results show that the ZnSe nanostructures have high wettability under UV light which has been shown to have excellent catalysis in the UV region, making its application as a self-cleaning material an attractive option. [ABSTRACT FROM AUTHOR]

In the present communication, structural and electrical properties of Y0.95Ca0.05MnO3 (YCMO) manganite thin films, having different thicknesses grown on (100) single crystalline Nb:SrTiO3 (SNTO) substrate using pulsed laser deposition (PLD) technique, have been investigated. Influence of 100 MeV O+7 energetic ion irradiation has been understood on the basis of structure–property correlations across the lattice of YCMO manganite. Influence of YCMO film thickness and ion fluence on the electrical properties have also been explored in the context of lattice strain, crystallite size (CS), crystallinity, defect state, local annealing effect and three dimensional disorder. YCMO/SNTO interface experiences the presence of tensile strain which is found to vary between +1.02 and +1.88% for 100 nm YCMO/SNTO thin film whereas it is found to decrease monotonically from +1.50 to +0.98% for 200 nm and +1.40 to +0.92% for 300 nm upon increase in ion fluence. For higher thicknesses of YCMO/SNTO films (i.e. 200 and 300 nm), CS (estimated using Scherrer's formula) is found to increase from 19.73 nm for pristine to 25.01 nm for higher influence irradiated 200 nm film and from 24.91 nm for pristine to 27.97 nm for higher influence irradiated 300 nm film which has been ascribed to the local annealing effect across the YCMO/SNTO thin film lattices. Variation in dielectric constant with frequency, YCMO layer thickness and ion fluence has been understood on the bases of lattice strain, defect state, CS, crystallite boundaries, dipolar relaxation and universal dielectric response (UDR) model. Nature of ac conductivity has been understood well in the context of Jonscher's power law fits where correlated barrier hopping (CBH) mechanism has been confirmed as a responsible process for charge conduction across the YCMO/SNTO interfaces. Maximum barrier height (Wm) has been derived using its relation with power exponent from Jonscher's power law fits to ac conductivity data and its values are found to vary nonmonotonically between 0.3218 and 0.4849 eV for 100 nm YCMO/SNTO film however it gets enhanced from 0.2382 to 0.3820 eV for 200 nm and from 0.1977 to 0.2203 eV for 300 nm YCMO/SNTO films upon increase in oxygen ion fluence. These variations have been ascribed to the dominant impact of high resistive insulating nature of core of the YCMO crystallites and three dimensional disorder across YCMO manganite lattice. Present report serves a complex simultaneous impact of YCMO layer thickness, ion fluence and related structural aspects on the electrical properties of YCMO/SNTO films where defect state can be regenerated through well established experimental tool of SHI irradiation in a controlled way. The electric properties of YCMO/SNTO thin films are of paramount importance in a variety of technological applications and are of fundamental importance for materials science research. [ABSTRACT FROM AUTHOR]

Brain‐inspired computing, reconfigurable optical metamaterials, photonic tensor cores, and many other advanced applications require next‐generation phase‐change materials (PCMs) with better energy efficiency and a wider thermal and spectral range for reliable operations. Germanium ditelluride (GeTe2), with higher thermal stability and a larger bandgap compared to current benchmark PCMs, appears promising for THz metasurfaces and the controlled crystallization of atomically thin 2D materials. Using high‐energy X‐Ray diffraction supported by first‐principles simulation, the atomic structure in semiconducting pulsed laser deposition films and metallic high‐temperature liquids is investigated. The results suggest that the structural and chemical metastability of GeTe2, leading to disproportionation into GeTe and Te, is related to high internal pressure during a semiconductor–metal transition, presumably occurring in the supercooled melt. Similar phenomena are expected for canonical GeS2 and GeSe2 under high temperatures and pressures. [ABSTRACT FROM AUTHOR]

Polycrystalline structures of T-Nb2O5 and a remarkable H-Nb2O5 structure were successfully obtained in this work. This was achieved using a Nd:YAG laser in a pulsed laser deposition system at laser fluence values of 9.3, 13.4, 16.2, 21, and 25.2 J cm−2. Raman bands of the prepared films are shown and discussed. The optical bandgaps were estimated at 4.81 eV, 4.73 eV, 3.41 eV, 3.29 eV, and 3.21 eV. Photoluminescence (PL) analyses showed agreement with the estimated indirect bandgaps calculated from Tauc's plot for each prepared film. The surface average roughness and root-mean-square (RMS) roughness were also determined and are discussed. The surface morphology as illustrated by field-emission scanning electron microscopy (FE-SEM) reveals the obvious impact of laser energy density on the prepared films. Energy-dispersive x-ray (EDX) analyses revealed the highest stoichiometry attributed to a laser fluence of 21 J cm−2. [ABSTRACT FROM AUTHOR]

Integrating two-dimensional layered supercell (LSC) oxides and plasmonic Au nanostructures into one hybrid framework can open up multifunctionality tuning into a new level. In this work, Bi-based LSCs Bi3Fe2Mn2Ox and Bi2WO6 incorporated with secondary plasmonic Au and/or ferromagnetic La0.7Sr0.3MnO3 phases have been grown via pulsed laser deposition (PLD). Microstructural characterization results show the highly epitaxy film quality and distinct LSC structures despite the incorporated secondary phases. The nanocomposite films exhibit multiferroic and plasmonic responses due to the multi-phase coupling. This work provides a new approach of integrating self-assembled LSC-metal/oxide nanocomposite thin films for future multiferroics and spintronics device applications. [ABSTRACT FROM AUTHOR]

We present a systematic growth study of epitaxial RuO2(110) and IrO2(110) on TiO2(110) substrates by pulsed laser deposition. We describe the main challenges encountered in the growth process, such as a deteriorating material flux due to laser-induced target metallization or the delicate balance of under- vs over-oxidation of the "stubborn" Ru and Ir metals. We identify growth temperatures and oxygen partial pressures of 700 K, 1 × 10−3 mbar for RuO2 and 770 K, 5 × 10−4 mbar for IrO2 to optimally balance between metal oxidation and particle mobility during nucleation. In contrast to IrO2, RuO2 exhibits layer-by-layer growth up to 5 unit cells if grown at high deposition rates. At low deposition rates, the large lattice mismatch between film and substrate fosters initial 3D island growth and cluster formation. In analogy to reports for RuO2 based on physical vapor deposition [He et al., J. Phys. Chem. C 119, 2692 (2015)], we find these islands to eventually merge and grow to continue in a step flow mode, resulting in highly crystalline, flat, stoichiometric films of RuO2(110) (up to 30 nm thickness) and IrO2(110) (up to 13 nm thickness) with well-defined line defects. [ABSTRACT FROM AUTHOR]

This review focuses on the innovative use of laser techniques in developing and functionalizing biomimetic surfaces, emphasizing their potential applications in the medical and biological fields. Drawing inspiration from the remarkable properties of various natural systems, such as the water-repellent lotus leaf, the adhesive gecko foot, the strong yet lightweight spider silk, and the unique optical structures of insect wings, we explore the potential for replicating these features through advanced laser surface modifications. Depending on the nature and architecture of the surface, particular techniques have been designed and developed. We present an in-depth analysis of various methodologies, including laser ablation/evaporation techniques, such as Pulsed Laser Deposition and Matrix-Assisted Pulsed Laser Evaporation, and approaches for laser surface structuring, including two-photon lithography, direct laser interference patterning, laser-induced periodic surface structures, direct laser writing, laser-induced forward transfer, and femtosecond laser ablation of metals in organic solvents. Additionally, specific applications are highlighted with the aim of synthesizing this knowledge and outlining future directions for research that further explore the intersection of laser techniques and biomimetic surfaces, paving the way for advancements in biomedical applications. [ABSTRACT FROM AUTHOR]

The porous silicon (PSi) substrate was accurately synthesized using photoelectrochemical etching. A Nanofilm gallium nitride (GaN) was then precisely deposited on this PSi substrate using pulsed laser deposition (PLD). The x-ray diffraction (XRD) investigation revealed the GaN layer's distinct crystalline structure along the (002) plane, with a precise crystallite size of 21.57 nm. This precision in the deposition process enhanced both the surface morphology and film quality. In the atomic force microscope (AFM), oval particles were evenly distributed across the entire surface, and the RMS of the surface was 27 nm with a 20.63 nm surface roughness. A field emission scanning microscope (FESEM) image of the gallium nitride (GaN) films deposited at a wavelength of 532 nm showed that the GaN material had an evenly covered Psi surface. This reflected the presence of a smooth and even spread of round particles. The cross-sectional area of the GaN sheet had a thickness of 2.92 µm, demonstrating the precision of the deposition technique. The resulting GaN nanofilms demonstrate UV photoluminescence (P.L.), characterized by a wavelength peak of 363.7 nanometers, indicative of the GaN material. In addition, they display a red photoluminescence peak at 723 nanometers, corresponding to the PSi substrate. Under UV-visible light and photoluminescence (P.L.), the optical energy gaps of the GaN nanofilm and the PSi substrate were determined. The PSi substrate exhibited an optical energy gap of 2.1 electron volts, whereas the resulting gallium nitride nanofilms displayed multiple energy band gaps of 3.4 electron volts and 1.7 electron volts.

Abstract BiFeO3 (BFO) application in flexible wearable devices is garnering interest because of its unique ferroelectric and magnetic properties. However, the integration of high-quality BFO films onto flexible substrates presents significant technical challenges. Here, we successfully fabricated high-quality BFO films on mica substrates by using pulsed laser deposition, and report the fatigue characteristics of BFO films on flexible substrates for the first time. The results demonstrated that, after 108 bipolar switching cycles, the polarization only degraded by 0.28%, indicating superior fatigue characteristics compared to previously reported BFO films. Additionally, the device ferroelectric properties remained largely unchanged, with a bending radius of 3.5 mm. The fabricated flexible Pt/BFO/La0.65Sr0.35MnO3(LSMO)/SrTiO3(STO)/mica non-volatile memory devices exhibited mechanical flexibility and fatigue resistance. These findings not only highlight the potential of flexible BFO films for wearable electronic devices and flexible memory devices, they also provide valuable insight for the future development of high-performance flexible ferroelectric materials.

The present study is focused on the investigation at 400 K of the tetragonal-rutile phase of Cr-doped VO2 (CVO) thin films grown by pulsed laser deposition. Synchrotron-based x-ray measurements of both the surface-sensitive total electron yield (TEY) and bulk-sensitive total fluorescence yield (TFY) modes were used to investigate the pristine and Cr-doped VO2 (5%, 10%, 20%, and 30% of atomic weight). The structural analysis and purity of the crystalline phase of the as-deposited films are manifested via grazing incidence x-ray diffraction patterns, which confirm the tetragonal-rutile phase. The purity of the phase is also confirmed by the presence of Eg-mode phonons in the Raman spectra and its deconvolution reflects on the oxygen-mediated electronic/vibrational transitional effect. A clear hysteretic behavior obtained through vibrating sample magnetometry strongly suggests the ferromagnetic interaction in the thin films of CVO. The local-electronic property of the samples is examined using x-ray absorption spectroscopy (XAS) in TEY and TFY modes where the difference in the configured helicity photons resulted in the fine spectra of x-ray magnetic circular dichroism (XMCD). XAS and XMCD measurements performed at V L2,3 and Cr L2,3 edges explicitly demonstrate the ferromagnetism in the thin films of CVO. The strong hybridization between V 3d and Cr 3d states with O 2p states is evident from the spectra of the O K-edge, resulting in the onset of the cation-pair formation V5+–Cr3+, which is ferromagnetic by means of double-exchange interaction. The theoretical calculation of density functional theory made upon Vienna ab initio simulation package suggests that CVO is in a mixed state of a ferromagnetic-insulator and a half-metallic ferromagnet. [ABSTRACT FROM AUTHOR]

A semiconductive oxide, La2CuO4 (LCO), was investigated as a potential material to compose photocathode for sunlight-driven hydrogen evolution by splitting water. LCO, despite involving partially filled Cu 3d orbitals, behaves as a semiconductor and absorbs visible light on the bandgap formed by significant Coulomb repulsion between the electronic orbitals. An epitaxial LCO film was grown on a SrRuO3/SrTiO3 (SRO/STO) single-crystal substrate by pulsed laser deposition to obtain a photocathodic specimen for water photo-splitting. An LCO photocathode dressed with a Pt cocatalyst for hydrogen evolution (Pt/LCO/SRO/STO) exhibited a cathodic photocurrent with a density of 0.4 mA cm−2 at 0 VRHE under simulated AM1.5 G sunlight. This photocathode responded to incident light up to 800 nm, which is one of the longest wavelengths so far reported for an oxide photoelectrode. Together with a counter-electrode for oxygen evolution, the Pt/LCO/SRO/STO photocathode generated hydrogen with the expected H2 : O2 = 2 : 1 stoichiometric ratio with a Faradaic efficiency of approximately 80%. [ABSTRACT FROM AUTHOR]

Obtaining Heusler alloys at the nanoscale with good crystallographic features is appealing for a large range of technological applications, from biomedical to spintronics devices. In particular, Fe 2 CrAl as bulk is known to present magnetic properties that are strongly sensitive to chemical and physical constraints, such as structural disorder and chemical composition. We report a throughout structural, morphological, and magnetic characterization of Fe 2 CrAl Heusler nanoparticles obtained by pulsed laser deposition technique. The nanoparticles are composed of slightly off-stoichiometric grains with two distinct morphologies where the role of chemical disorder and inhomogeneity on the magnetic behavior was evaluated. Through DC magnetization measurements, a superparamagnetic behavior is observed and a Gilbert damping of 9 × 10 − 3 is acquired from broadband ferromagnetic resonance data, which is comparable with standard materials used for magnonics applications. We discuss the complex magnetostructural coupling that rises on the nanoparticle system, comparing these results with the stoichiometric Fe 2 CrAl bulk target behavior. [ABSTRACT FROM AUTHOR]

This study deals with the effect of Cu on hydroxyapatite (HAp) thin films on silicon substrates prepared by pulsed laser deposition (PLD) technique for Cu concentrations ranging from 0 to 0.8 wt.%. Fourier transform infrared spectroscopy and Raman spectroscopy provide additional evidence of HAp in the films, which exhibit characteristic HAp bands such as the 960 cm−1 phosphate ion band. The X‐ray diffraction patterns confirm the presence of HAp, without copper‐related peaks, suggesting that it is not incorporated into the HAp lattice, which is present as an amorphous phase. X‐ray photoelectron spectroscopy confirms the presence of Cu on the HAp thin films, possibly related to the adsorption of Cu2+ on HAp surfaces through electrostatic or interactions with (PO4)3− groups. Atomic force microscopy shows that the roughness of the films varies depending on the presence or absence of copper ions. Finally, density functional theory and kinetic Monte Carlo simulations explain the effects of atomic diffusion on roughness and HAp clustering. These changes correlate with the contact angle values, indicating the formation of hydrophobic films due to copper inclusions. [ABSTRACT FROM AUTHOR]

High entropy oxides (HEOs) have garnered much interest due to their available high degree of tunability. Here, we study the local structure of (MgNiCuCoZn)0.167(MnCr)0.083O, a composition based on the parent HEO (MgNiCuCoZn)0.2O. We synthesized a series of thin films via pulsed laser deposition at incremental oxygen partial pressures. X‐ray diffraction shows lattice parameters to decrease with increased pO2 pressures until the onset of phase separation. X‐ray absorption fine structure shows that specific atomic species in the composition dictate the global structure of the material as Cr, Co, and Mn shift to energetically favorable coordination with increasing pressure. Transmission electron microscopy analysis on a lower‐pressure sample exhibits a rock salt structure, but the higher‐pressure sample reveals reflections reminiscent of the spinel structure. In all, these findings give a more complete picture of how (MgNiCuCoZn)0.167(MnCr)0.083O forms with varying initial conditions and advances fundamental knowledge of cation behavior in high entropy oxides. [ABSTRACT FROM AUTHOR]

Nanostructure control is of fundamental and technological importance because various properties such as vortex pinning in superconductors are determined by the nanostructure. While the nanostructure in superconducting oxides is well controlled, the nanostructure control of iron-based superconductors is required. The nanostructure has not yet been well controlled even in Fe(Te,Se) with the simplest structure among Fe-based superconductors because the anion may be non-stoichiometric and anionic substitution is possible. In this study, we observed the compositional inhomogeneity originating from phase separation in Fe(Te,Se) films, which were prepared by pulsed laser deposition. The films deposited at lower temperature do not show nanoscale compositional inhomogeneity. On the other hand, the high-temperature deposited films contain an inhomogeneous anion distribution with the size of ∼8 nm due to phase separation. The spacing of the compositional inhomogeneity is ∼16 nm. This structure obtained by phase separation is expected to be an effective pinning center in high magnetic fields after further optimization. Thus, the method of nanostructure control other than nanocomposite formation in oxides is demonstrated for Fe(Te,Se). [ABSTRACT FROM AUTHOR]

We report a systematic study of free-space terahertz (THz) emission from photoconductive antennas (PCAs) nanodecorated with gold nanoparticles (Au-NPs) deposited by using the pulsed laser deposition (PLD) technique. H-shaped dipole micro-structured PCAs fabricated on semi-insulating GaAs substrates were decorated under various PLD conditions. Thus, by increasing the number of laser ablation pulses (NLP) of the Au target, both the average size of Au-NPs and the surface loading of PCAs increase. Compared with non-decorated PCAs, those decorated with Au-NPs exhibit significant enhancement in the radiated THz pulse amplitude. A maximum enhancement of ∼2.3 was achieved at NLP = 1250. Under this optimal NLP condition, not only is the average Au-NP size (of ∼15 nm) favorable for light absorption via localized surface plasmons, but also the inter-distance between NPs, the light reflectance, and facilitated transport of photocarriers, all combine to yield a stronger THz field emission. For higher NLP (≥2000), NPs coalesce and tend to form continuous film NPs, which not only significantly limits the light scattering toward the GaAs underlying substrate, but also electrically shorts the PCA. Finally, the Au-NP decoration of GaAs PCAs was also found to improve their overall thermal conductivity, making them much more thermally stable than their non-decorated counterparts. [ABSTRACT FROM AUTHOR]

Exotic topological domains in BiFeO3 nanoislands have attracted much attention regarding their potential applications in advanced electronic devices. Here, different from the earlier reported disordered distributed BiFeO3 nanoislands formed by a self-assembly method, we fabricated an ordered BiFeO3 nanoisland array by mask-assisted pulsed laser deposition on a SrTiO3 substrate, which exhibits a center-converged in-plane polarization component and a monodomain pattern along the vertical direction. Such center-type quad-domain structures exhibit high stability, maintaining their topological structures after heating to 250 °C and subsequently cooling to room temperature. Moreover, they can be switched by applying a scanning electric field and recovered by applying a heating and cooling process. Observing this topological structure in BiFeO3 nanoislands might provide a suitable platform for further exploration of its topological phase transition properties, new functions, and potential applications. [ABSTRACT FROM AUTHOR]

Abstract The structural, surface, and upconversion (UC) luminescence properties of Y2O3:Ho3+,Yb3+ films grown by pulsed laser deposition, for different numbers of laser pulses, were studied. The crystallinity, surface, and UC luminescence properties of the thin films were found to be highly dependent on the number of laser pulses. The X-ray powder diffraction analysis revealed that Y2O3:Ho3+,Yb3+ films were formed in a cubic structure phase with an Ia $$\overline{3 }$$ 3 ¯ space group. The thicknesses of the films were estimated by using cross-sectional scanning electron microscopy, depth profiles using X-ray photoelectron spectroscopy (XPS), and the Swanepoel method. The high-resolution XPS was used to determine the chemical composition and oxidation states of the prepared films. The UC emissions were observed at 538, 550, 666, and 756 nm, assigned to the 5F4 → 5I8, 5S2 → 5I8, 5F5 → 5I8, and 5S2 → 5I7 transitions of the Ho3+ ions. The power dependence measurements confirmed the involvement of a two-photon process in the UC process. The color purity estimated from the Commission International de I’Eclairage coordinates confirmed strong green UC emission. The results suggested that the Y2O3:Ho3+,Yb3+ UC transparent films are good candidates for various applications, including solar cell applications.

Antiferroelectrics have recently captured widespread attention for their potential applications in energy storage capacitors, electronic and electrothermal devices. PbZrO3, being the first antiferroelectric discovered, remains the focus of antiferroelectric studies. Conventionally, the PbZrO3 ceramics were prepared via a high-temperature solid-state reaction method (higher than 1000∘C). Here, we report a simple sol–gel route to prepare single-phase PbZrO3 ceramic at a much lower calcination temperature of 600∘C. By using the single-phase PbZrO3 ceramics, thin films with outstanding antiferroelectric property showing well-defined double-hysteresis polarization switching were further obtained by pulsed laser deposition. [ABSTRACT FROM AUTHOR]

The ordinary dielectric functions (DFs) of rutile GexSn1−xO2 thin films grown by pulsed laser deposition have been obtained by spectroscopic ellipsometry from the near infrared to the ultraviolet range. Additionally, the Ge content x and the lattice parameters were determined by energy dispersive x-ray spectroscopy and x-ray diffraction, respectively. The lattice parameter deviates partly from Vegard's law due to epitaxial strain. In the DFs, a blue shift of the onset of absorption with increasing Ge content is observed. Evaluation of the DFs yields the characteristic transition energies at the absorption onset, and the corresponding bowing parameter of the dipole allowed direct bandgap of b = (0.70 ± 0.09) eV. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Chemical Communications" published in 2024. It includes various articles on topics such as responsive theranostic agents, cationic ligands, green synthesis of zeolite, and transition metal oxide clusters. The journal is published by The Royal Society of Chemistry and focuses on connecting the world with the chemical sciences. The document provides a comprehensive overview of the articles included in the journal issue. [Extracted from the article]

Different conditions are explored to understand their effects on the pulsed laser deposition of BiVO4 water splitting photoanodes, over YSZ (110) substrates. A two-step deposition (TSD) method can independently tune nucleation and bulk film growth, leading to the formation of a phase pure, crystalline BiVO4 film with optimized water splitting activities. [ABSTRACT FROM AUTHOR]

The ordinary dielectric functions (DFs) of rutile GexSn1−xO2 thin films grown by pulsed laser deposition have been obtained by spectroscopic ellipsometry from the near infrared to the ultraviolet range. Additionally, the Ge content x and the lattice parameters were determined by energy dispersive x-ray spectroscopy and x-ray diffraction, respectively. The lattice parameter deviates partly from Vegard's law due to epitaxial strain. In the DFs, a blue shift of the onset of absorption with increasing Ge content is observed. Evaluation of the DFs yields the characteristic transition energies at the absorption onset, and the corresponding bowing parameter of the dipole allowed direct bandgap of b = (0.70 ± 0.09) eV. [ABSTRACT FROM AUTHOR]

Autonomous systems that combine synthesis, characterization, and artificial intelligence can greatly accelerate the discovery and optimization of materials, however platforms for growth of macroscale thin films by physical vapor deposition techniques have lagged far behind others. Here this study demonstrates autonomous synthesis by pulsed laser deposition (PLD), a highly versatile synthesis technique, in the growth of ultrathin WSe2 films. By combing the automation of PLD synthesis and in situ diagnostic feedback with a high‐throughput methodology, this study demonstrates a workflow and platform which uses Gaussian process regression and Bayesian optimization to autonomously identify growth regimes for WSe2 films based on Raman spectral criteria by efficiently sampling 0.25% of the chosen 4D parameter space. With throughputs at least 10x faster than traditional PLD workflows, this platform and workflow enables the accelerated discovery and autonomous optimization of the vast number of materials that can be synthesized by PLD. [ABSTRACT FROM AUTHOR]

Nanostructured photodetectors have garnered great attention due to their enriched electronic and optical properties. In this work, we aim to fabricate a high-performance CeO2/Si photodetector by growing a CeO2 nanostructure film on a silicon substrate using the pulsed laser deposition (PLD) technique at different laser energy densities. The impact of laser energy density and the number of pulses on the morphological, optical, and electrical properties was studied. Field emission scanning electron microscopy (FESEM) results show that the CeO2 film has a spherical grain morphology with an average grain size ranging from 33 to 54 nm, depending on the laser energy density. The film deposited at various numbers of laser pulses also has spherical grains with an average grain size ranging from 39 to 54 nm, depending on the number of pulses. The optical properties of the CeO2 film showed that the optical energy gap of the films decreased from 3.5 to 3 eV as the laser energy density increased from 63.66 to 101.86 J/cm2. The photoluminescence (PL) spectra of the nanostructured CeO2 film reveal that the main emission peaks were observed at 682 nm when excited at 450 nm. The effect of laser energy density on the electrical properties, including carrier concentration, mobility, and current-voltage characteristics under dark and illuminated conditions, was investigated. The CeO2/Si photodetector fabricated at 63.66 J/cm2 showed the highest responsivity of 0.69 A/W at 450 nm, detectivity as high as 1.5 × 1010 Jones at 450 nm, and an external quantum efficiency of 92% when biased to 5 V. The photodynamic response time was measured. [ABSTRACT FROM AUTHOR]

Beta-phase gallium oxide (β-Ga2O3) is a cutting-edge ultrawide bandgap (UWBG) semiconductor, featuring a bandgap energy of around 4.8 eV and a highly critical electric field strength of about 8 MV/cm. These properties make it highly suitable for next-generation power electronics and deep ultraviolet optoelectronics. Key advantages of β-Ga2O3 include the availability of large-size single-crystal bulk native substrates produced from melt and the precise control of n-type doping during both bulk growth and thin-film epitaxy. A comprehensive understanding of the fundamental growth processes, control parameters, and underlying mechanisms is essential to enable scalable manufacturing of high-performance epitaxial structures. This review highlights recent advancements in the epitaxial growth of β-Ga2O3 through various techniques, including Molecular Beam Epitaxy (MBE), Metal-Organic Chemical Vapor Deposition (MOCVD), Hydride Vapor Phase Epitaxy (HVPE), Mist Chemical Vapor Deposition (Mist CVD), Pulsed Laser Deposition (PLD), and Low-Pressure Chemical Vapor Deposition (LPCVD). This review concentrates on the progress of Ga2O3 growth in achieving high growth rates, low defect densities, excellent crystalline quality, and high carrier mobilities through different approaches. It aims to advance the development of device-grade epitaxial Ga2O3 thin films and serves as a crucial resource for researchers and engineers focused on UWBG semiconductors and the future of power electronics. [ABSTRACT FROM AUTHOR]

We studied the interfacial spin Hall magnetotransport in the Tb3Fe5O12 (TbIG)/Pt system across a non-magnetic [Y3Al5O12 (YAG) and Gd3Ga5O12 (GGG)] spacer with garnet structure. TbIG (30 nm)/spacer samples were grown on single-crystal (GGG) (111) substrates by pulsed laser deposition before 5 nm of Pt was sputtered on the samples and patterned into Hall bars. The YAG spacer thickness (tYAG) dependences of anomalous Hall effect resistance (RAHE) indicated no significant change on the magnetization compensation temperature of TbIG. Hysteretic RAHE loops were observed at low magnetic fields, but with reducing magnitude as tYAG thickness increases. A crossover of the RAHE sign was observed at temperatures below the compensation temperature, which decreased sharply from 135 to 34 K as tYAG increased from 0 to 1 nm. We attributed this to the strong dependence of the magnetic proximity effect toward the YAG insertion in the TbIG/Pt interface. Replacement of the YAG spacer with GGG showed significant impact on the RAHE behavior. No obvious RAHE-H loops were observed in the TbIG/Pt sample inserted with 0.5 nm GGG spacer, which could be linked to the strong magnetic contribution of the Gd ions. This work highlights the tunability of interfacial transport behavior in iron garnet/heavy metal systems through ultrathin spacers, providing guidance for the interfacial design of spintronic devices. [ABSTRACT FROM AUTHOR]

The negative electric potential difference observed in a YSZ-based thin film potentiometric sensor at a low operating temperature of 673 K is investigated. The multilayered sensor is grown sequentially using pulsed laser deposition at 998 K with Cu-Cu2O reference electrode, YSZ electrolyte and Pt as working electrode respectively. The thickness of the Cu-Cu2O reference layer is a critical factor in thin film sensors as the Pt3O4 phase stabilized along with Cu-Cu2O can reach the YSZ interface. XRD, μ- Raman and XPS confirm the formation of the Pt3O4 phase on the reference side along with the Cu-Cu2O layer. However, the pure Pt3O4 phase could not be stabilized in the thin film without Cu-Cu2O. The presence of the Pt3O4 phase on the reference side generates a Pt-Pt3O4 reference couple with an equilibrium oxygen partial pressure of ~ 104 ppm higher than the sample oxygen pressure of 10-103 ppm giving rise to a negative electric potential difference with a sensitivity of -7.5 mV/decade. [ABSTRACT FROM AUTHOR]

Transparent conducting oxides are crucial in the field of optoelectronics, and SrNbO 3 has emerged as a promising candidate because it can outperform commonly used indium tin oxides due to its novel functionality. However, experimental investigations of SrNbO 3 are challenging because it undergoes topotactic phase transition to exhibit insulating behavior. Here, we investigate the pivotal role of SrNbO 3 stoichiometry to enhance its performance as a transparent conducting oxide. Results indicate the optoelectronic properties of SrNbO 3 are highly dependent on its intrinsic lattice parameters and stoichiometry. Films with lattice parameters close to those of pure SrNbO 3 exhibit excellent conductivity and transmittance in the visible range, while off-stoichiometry diminishes optoelectronic properties. Our stoichiometric sample demonstrates a record-high figure of merit for SrNbO 3, considerably surpassing that of indium tin oxide by an order of magnitude. Thus, this study paves the way for production of high-quality SrNbO 3 and leveraging its novel functionalities in optoelectronic applications. [ABSTRACT FROM AUTHOR]

The combination of common semiconductors with porous materials has the potential to augment the splitting of electrons and holes, hence increasing the efficiency of gases-sensitive. This study examines the unique sensitivity shown by Pd/WO3 films that were fabricated via the use of the pulsed laser deposition technique on a substrate composed of porous silicon for the purpose of detecting hydrogen sulphide (H2S) and nitrogen dioxide (NO2) over a wide range of temperatures. Tungsten trioxide films doped with palladium (Pd/WO3) are fabricated using pulsed laser deposition at varying laser pulse energies (600, 800, and 1000 mJ/pulse). The ablation process involves the use of a Q-switched Nd/YAG laser operating at a wavelength of 532 nm. The laser system being examined demonstrates pulse duration of 10 ns and a frequency of 1 Hz when used on a porous silicon n-type Si (100) substrate. The study of Pd/WO3 nanoparticles involves the analysis of their crystal structure, optical properties, and morphology through various analytical methods such as X-ray diffraction, UV–Vis spectroscopy, Raman scattering, photoluminescence spectroscopy, and field-emission scanning electron microscopy. The increase in intensity of the pulse laser results in a heightened sharpness of the peaks detected in the Pd/WO3 thin film, indicating an enhancement in crystallinity. The dimensions of the surface particles have shown a rise, followed by a corresponding augmentation in the energy difference, resulting in a heightened degree of uniformity. The study aimed to examine the influence of Pd on the development kinetics of tungsten trioxide nanoparticles. The findings demonstrated that Pd had the capacity to augment sensitivity, reduce operational temperature, and maintain high sensitivity levels even at room temperature. The Pd/WO3 NPs/porous silicon device fabricated in this work, consisting of a Pd/WO3 nanostructure integrated with porous silicon, has remarkable potential as a high-efficiency gas sensor in several sensing technologies. [ABSTRACT FROM AUTHOR]

Ca-doped BiFeO3/LaNiO3/LaAlO3 (BCFO/LNO/LAO) heterostructures have garnered significant interest due to their unique combination of ferroelectric, magnetic, and resistive switching properties due to interfaces and lattice mismatch/strain, leading to unique electronic properties. The roles of structural defects and oxygen vacancies are important in achieving the magnetic and electrical properties of BiFeO3-based heterostructures. By generating defects, swift heavy ion irradiation can lead to changes in the structural, optical, electrical, and magnetic properties of the materials. The Ca-doped BiFeO3 and LaNiO3 heterostructure was grown upon LAO substrates using the pulsed laser deposition technique, ensuring high-quality interfaces and controlled thicknesses. The heterostructures were irradiated with 80 MeV O+7 ions at various ion fluence levels (5 × 1010 ions/cm2 to 5 × 1012 ions/cm2). The structure and crystalline orientation of the thin films were confirmed through x-ray diffraction, while the surface morphology was measured using atomic force microscopy. Irradiation-induced modifications of the structural strain and surface morphology were investigated in the context of internal annealing effect and defect formation. The resistive switching (RS) properties of the proposed devices were assessed by I–V measurement with sweeping 0 → 5 V → 0 → − 5 V → 0, which shows that irradiation-induced defects play an important role in the electrical properties of the proposed heterostructure. Bipolar RS behavior was also verified with the conduction mechanism, indicating that the ohmic and space-charge-limited conduction mechanism plays an important role in irradiated BCFO/LNO/LAO heterostructures. Graphical representation of the defect formation and RS behavior due to varying ion fluence as a function of RMS roughness and strain. [ABSTRACT FROM AUTHOR]

Developing novel lead‐free ferroelectric materials is crucial for next‐generation microelectronic technologies that are energy efficient and environment friendly. However, materials discovery and property optimization are typically time‐consuming due to the limited throughput of traditional synthesis methods. In this work, we use a high‐throughput combinatorial synthesis approach to fabricate lead‐free ferroelectric superlattices and solid solutions of (Ba0.7Ca0.3)TiO3 (BCT) and Ba(Zr0.2Ti0.8)O3 (BZT) phases with continuous variation of composition and layer thickness. High‐resolution x‐ray diffraction (XRD) and analytical scanning transmission electron microscopy (STEM) demonstrate high film quality and well‐controlled compositional gradients. Ferroelectric and dielectric property measurements identify the "optimal property point" achieved at the composition of 48BZT–52BCT. Displacement vector maps reveal that ferroelectric domain sizes are tunable by varying {BCT–BZT}N superlattice geometry. This high‐throughput synthesis approach can be applied to many other material systems to expedite new materials discovery and properties optimization, allowing for the exploration of a large area of phase space within a single growth. [ABSTRACT FROM AUTHOR]

As a potential upconverting layer for solar cell applications, the effect of substrate temperature on the structural, surface, and upconversion (UC) properties of Y2O3:Ho3+,Yb3+ thin films was studied. On soda-lime glass substrates, pulsed laser deposition was used to generate the films. The structural and compositional analyses were performed using x-ray powder diffraction and x-ray photoelectron spectroscopy (XPS). The thicknesses of the prepared films were estimated using XPS depth profiles and cross-sectional scanning electron microscopy measurements. The UC and cathodoluminescence emissions revealed green, red, and infrared emission bands from Ho3+ ion transitions observed at 540, 550, 668, and 757 nm, corresponding to the 5F4 → 5I8, 5S2 → 5I8, 5F5 → 5I8, and 5S2 → 5I7 transitions under 980 nm excitation and high-energy electron excitation, respectively. The measurements of power dependency showed that a two-photon step method was used to proceed with the UC emission. Furthermore, the UC energy transfer process was thoroughly explored. The efficient UC emission results suggested that the Y2O3:Ho3+,Yb3+ films can be suitable for solar cell applications. [ABSTRACT FROM AUTHOR]

Multi-phase vertically aligned nanocomposite (MP-VAN) thin films represent a promising avenue for achieving complex multifunctionality, exploring novel interfacial phenomena, and enabling complex metamaterial designs and exploration. In this study, a novel self-assembled all-oxides three-phase VAN system was conceptualized and fabricated utilizing pulsed laser deposition (PLD) with a single composite target. Detailed microstructural analysis reveals the presence of three distinct phases: LiNbO3, CeO2−x, and LiNbCe1−xOy within the MP-VAN films. Subsequently, ferroelectric, dielectric, optical anisotropy, and magnetic properties were systematically investigated to showcase the multifunctionality inherent in these films. This work presents a pioneering approach to designing and realizing MP-VAN systems, and opens up opportunities for tailoring the complex three-dimensional (3D) physical properties and property coupling of VAN films towards diverse device applications. [ABSTRACT FROM AUTHOR]

As devices become more miniaturized and integrated, the heat flux density has increased, highlighting the issue of heat concentration, especially for low thermal conductivity gallium oxide (Ga2O3). This study utilizes diamond composite substrates with an AlN transition layer to assist Ga2O3 in rapid thermal dissipation. All samples were prepared using pulsed laser deposition (PLD) and annealed at 600–1000 °C. The microstructure, surface morphology, vacancy defects, and thermal characteristics of post-annealed Ga2O3 were then thoroughly investigated to determine the mechanism by which annealing temperature influences the heat transfer of heterostructures. The results demonstrate that increasing the annealing temperature can improve the crystallinity of Ga2O3 while also reducing oxygen vacancy defects from 20.6% to 9.9%. As the temperature rises to 1000 °C, the thermal conductivity of Ga2O3 reaches a maximum of 12.25 W/(m·K). However, the interface microstructure has no direct correlation with annealing temperature. At 700 °C, Ga2O3/diamond exhibits a maximum thermal boundary conductance of 127.06 MW/(m2·K). Higher temperatures (>800 °C) cause irregular mixtures to form near the heterointerface, intensifying phonon interface scattering and sharply deteriorating interfacial heat transfer. These findings contribute to a better understanding of the heterointerface thermal transfer influence mechanism and provide theoretical guidance for the thermal management design and physical analysis of Ga2O3-based power devices. [ABSTRACT FROM AUTHOR]

Carbon nanotubes, as carbon allotropes distinguished by their intricate structures and exceptional physicochemical properties, have demonstrated substantial progress in recent years across diverse domains, including energy production, chemical synthesis, and environmental preservation. They exhibit notable attributes such as high thermal stability, superior adsorption capacity, and a substantial specific surface area, rendering them superb catalyst supports. Particularly in electrochemical energy storage, CNTs are extensively employed in supercapacitor electrodes owing to their elevated electrical conductivity, mechanical robustness, and electrocatalytic prowess, which facilitate significant energy storage capabilities. Their intricate pore architecture and reactive sites make functionalized carbon nanotubes well suited for synthesizing composite materials with diverse components, which are ideal for sequestering carbon dioxide from both atmospheric and indoor environments. This review presents a comprehensive examination of carbon nanotube synthesis methodologies, encompassing chemical vapor deposition, arc discharge, and laser ablation, and evaluates their impacts on the structural and functional properties of carbon nanotubes. Furthermore, this article underscores the applications of carbon nanotubes in fields such as fuel cells, photocatalysis, ammonia synthesis, dry methane reforming, Fischer–Tropsch synthesis, and supercapacitors. Despite the considerable potential of carbon nanotubes, their manufacturing processes remain intricate and costly, impeding large-scale industrial production. This review concludes by addressing the challenges in fabricating carbon nanotube composites and outlining future development prospects. [ABSTRACT FROM AUTHOR]

Thin film solar cells are gaining popularity as an affordable, efficient, and flexible substitute for traditional silicon solar cells . This success is closely tied to the deposition techniques used to fabricate their layers. This review explores and analyzes the advances in the major deposition techniques for solar cell applications, offering insights into their underlying principles, associated advantages, drawbacks, and suitability for diverse materials and device architectures. The two primary deposition for thin film solar cells are PVD and CVD. In PVC materials are physically ejecting from a target, and depositing it onto a substrate. While, CVD entails the reaction of gases or vapour precursors to creating film on a substrate. The ability to achieve high purity, control over film properties, scalability, and compatibility with flexible substrates are notable advantages. However, challenges such as high costs and complexity can impact the commercial viability of certain techniques. Recent advancements in the technology of thin film deposition for solar cells include the discovery of novel materials with enhanced light absorption and electronic charge transport capabilities, emerging deposition processes such as pulsed laser deposition, and atomic layer deposition scalable and low-cost processes like roll-to-roll processing, and integration with other technologies like perovskite solar cells and tandem devices. Understanding these techniques and staying informed about recent advancements and future directions empowers researchers and engineers to innovate and create improved thin film solar cells, contributing significantly to a more sustainable future through enhanced solar energy harvesting technologies. [ABSTRACT FROM AUTHOR]

High-TC cuprate superconductors' growth conditions and their incompatibility with some of the most standard nanofabrication approaches make their large-scale integration with 2D materials (such as graphene, transition metal dichalcogenides, and other Van der Waals materials) much more difficult than for conventional, metallic superconductors. Here, we address this challenge and develop an approach based on pulsed laser deposition that allows the growth of the 2D semiconductor MoS2 on the archetypal high-TC superconductor YBa2Cu3O7−x. This yields functional heterostructures in which the individual constituents' properties are preserved and that show superconducting coupling across their interface. The developed approach paves the way for large-scale 2D semiconductor co-integration with high-TC superconductors toward the study and leverage of the superconducting proximity effect in hybrid devices. [ABSTRACT FROM AUTHOR]

Layered perovskite-structured thin films of SrBi2Ta2O9 (SBT) were successfully deposited onto highly oriented pyrolytic graphite substrates using a pulse laser deposition technique, resulting in an atomic structure identical to that of the graphene surface. The SBT thin films exhibited enhanced ferroelectric and dielectric properties when the substrate temperature was slightly lowered, attributed to the improvement in a-oriented crystallinity. Due to the enhancement in a-oriented crystallinity, the SBT thin films exhibited an improved remanent polarization of approximately 12.3 μC/cm2 and an enhanced remanent piezoelectric coefficient of approximately 13.6 pm/V. The observations of ferroelectric domain structures using piezoresponse force microscopy confirmed a slight increase in domain boundary energy for SBT thin films with enhanced a-oriented crystallinity. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3), with an ultrawide bandgap corresponding to the deep ultraviolet (DUV) range, has attracted significant attention in optical filter‐free photodetectors. In practical terms, DUV photodetectors employed in extreme conditions, for example, flame detection and space exploration, face the challenges of performance degradation caused by high/low‐temperature transformation. Here, DUV photodetectors are tailored with high durability and stability by one‐step‐grown β‐Ga2O3 films via pulsed laser deposition. A high‐oxygen‐pressure scheme effectively addresses the issue of film‐free deposition at specifically high temperatures, facilitating the formation of polycrystalline high‐resistivity β‐Ga2O3 films. As a result, the devices exhibit outstanding performance, including a low dark current (4.4 pA @30 V), high photoresponsivity (147.36 A W−1), and fast response time (3.1/22.6 ms). Additionally, the photoresponse performance shows minimal degradation at high temperatures up to 300 °C and even improves at low temperatures down to −100 °C, ranking it among the most robust DUV photodetectors. The mechanism of photoresponse, involving the exciton formation, bandgap evolution, carrier‐phonon scatter, etc., is also elucidated in a wide temperature range. This work provides an efficient solution for developing robust Ga2O3 DUV photodetectors with excellent performance for extreme‐condition applications. [ABSTRACT FROM AUTHOR]

High-quality epitaxial BiFeO3 (BFO) films were grown on (001)-, (110)- and (111)-oriented Nb:SrTiO3 (NSTO) substrates by pulsed laser deposition. The type of domain structure can be modulated using BFO ferroelectric films with different crystalline orientations. The ON/OFF ratios obtained in (001)-, (110)- and (111)-oriented Au/BFO/NSTO ferroelectric tunnel junctions (FTJs) are 6 × 103, 3 × 104 and 2 × 105, respectively. Analysis of the I – V curves of tunnelling current and average BFO ferroelectric barrier height proves that the polarization intensity of the BFO films modulates both the ferroelectric barrier and the Schottky barrier profile, which further influences the electronic tunnelling probability in BFO FTJs. This work will be useful for further study on achieving a giant ON/OFF ratio and developing insights into the barrier profile and transport mechanism of metal/ferroelectric/semiconductor-type FTJs. [ABSTRACT FROM AUTHOR]

The observation of superconductivity in MnSe at 12 GPa motivated us to investigate whether superconductivity could be induced in MnSe at ambient conditions. A strain-induced structural change in the ultrathin film could be one route to the emergence of superconductivity. In this report, we present the physical property of MnSe ultrathin films, which become tetragonal (stretched ab-plane and shortened c-axis) on a (001) SrTiO3 (STO) substrate, prepared by the pulsed laser deposition (PLD) method. The physical properties of the tetragonal MnSe ultrathin films exhibit very different characteristics from those of the thick films and polycrystalline samples. The tetragonal MnSe films show substantial conductivity enhancement, which could be associated with the presence of superparamagnetism. The optical absorption data indicate that the electron transition through the indirect bandgap to the conduction band is significantly enhanced in tetragonal MnSe. Furthermore, the X-ray Mn L-edge absorption results also reveal an increase in unoccupied state valance bands. This theoretical study suggests that charge transfer from the substrate plays an important role in conductivity enhancement and the emergence of a ferromagnetic order that leads to superparamagnetism. [ABSTRACT FROM AUTHOR]

Piezoelectric and ferroelectric wurtzite are promising to reshape modern microelectronics because they can be easily integrated with mainstream semiconductor technology. Sc doped AlN (Al1‐xScxN) has attracted much attention for its enhanced piezoelectric and emerging ferroelectric properties, yet the commonly used sputtering results in polycrystalline Al1‐xScxN films with high leakage current. Here, the pulsed laser deposition of single crystalline epitaxial Al1‐xScxN thin films on sapphire and 4H‐SiC substrates is reported. Pure wurtzite phase is maintained up to x = 0.3 with ≤0.1 at% oxygen contamination. Polarization is estimated to be 140 µC cm−2 via atomic scale microscopy imaging and found to be switchable via a scanning probe. The piezoelectric coefficient is found to be five times of the undoped one when x = 0.3, making it desirable for high‐frequency radiofrequency (RF) filters and 3D nonvolatile memories. [ABSTRACT FROM AUTHOR]