Search

Today, the earnest need for earth-abundant and environmentally friendly thermoelectric materials has revealed the importance of semiconductor metal oxides in order to eliminate the barrier towards their wide-ranging use in industrial applications. In the present work, we demonstrate the synthesis of p-type tin oxide thin films on quartz glass and Si substrates by using electron beam evaporation technique followed by rapid thermal annealing process at 200 °C for 20 min in Ar-atmosphere. Annealing-induced structural, electrical, optical and thermoelectric properties of pristine and annealed SnO thin films are primarily studied. The compositional and structural analysis of SnO films are performed by using X-Ray Diffraction, Scanning Electron Microscope as well as Atomic Force Microscope. Moreover, the mechanism of thermoelectric transportation at different measurement temperatures is deeply inspected via thermoelectric measurements. The Seebeck coefficient, carrier concentration and hole mobility in conjunction with the development of thin film nanostructures are discussed, predominantly. The optimal annealing may tune structural, electro-optic and thermoelectric properties of SnO films for the commercial-level maturity of thermoelectric devices for energy applications.

Vacuum-air-shift causes trouble to conventional electron beam evaporation (EBE) coatings. This study compares the protection effect of ion assistance and the ALD (atomic layer deposition) Al2O3 capping layer. The vacuum-air-shift was reproduced on an EBE Ta2O5 single-layer film, a Ta2O5/SiO2 double-layer coating, and a high-reflectance mirror. Similar samples were prepared by EBE assisted with ion beam bombardment. Part of the as-deposited coatings were capped by ALD Al2O3 film with a thickness of about 100 nm. The vacuum-air-shift of the samples was tested with an in-situ spectrophotometer. The cross-section of the coatings was imaged by a scanning electron microscope. The ion assistance was found to reduce the vacuum-air-shift to a limit extent, while the ALD capping film was found to eliminate the vacuum-air-shift. The mechanism of the two protection techniques was analyzed, and their usage was compared and discussed. The ALD capping technique may be used in high precision EBE coatings with convenience and low cost.

An ultrasensitive Ag-deposited TiO2 flower-like nanomaterial (FLNM) surface-enhanced Raman scattering (SERS)-active substrate is synthesized via a hydrothermal method, and Ag nanoparticles (NPs) are deposited through electron beam evaporation. Malachite green (MG), which is widely used in aquaculture, is employed to assess the surface-enhanced Raman scattering (SERS) properties of TiO2/Ag FLNMs. They exhibit ultrasensitivity (limit of detection (LOD) of MG reaches 4.47 × 10-16 M) and high reproducibility (relative standard deviations (RSDs) are less than 13%); more importantly, the TiO2/Ag FLNMs are recyclable, as enabled by their self-cleaning function due to TiO2 photocatalytic degradation. Their recyclability is achieved after three cycles and their potential application is examined in the actual system. Finite difference time domain (FDTD) simulations and the charge-transfer (CT) mechanism further prove that the excellent SERS properties originate from localized surface plasmon resonance (LSPR) of Ag NPs and the coupling field between Ag and TiO2 FLNMs. Therefore, TiO2/Ag FLNMs show promising application in aquaculture.

We investigated the design and fabrication of liquid crystal polymer phase retarder. The liquid crystal polymer was aligned with the inorganic dielectric layer by glancing angle deposition. The ret...

Metal-ceramic nanocomposite coatings have been applied to many industrial applications owing to their remarkable properties such as wear, corrosion and high temperature oxidation resistance than that of metals and alloys in high temperature environments. In this study, YSZ and Ni-YSZ nanocomposite coatings deposited by electron beam physical vapour deposition (EBPVD) for high temperature environments have been investigated. Initially friction and wear behaviour of YSZ coatings deposited at various substrate temperature were studied. Then the effect on wear response of Ni-YSZ nanocomposites with different Ni content were investigated using a ball-on-disc micro tribometer. The structural and tribochemical changes that occurred in the wear tracks of YSZ and Ni-YSZ coatings were investigated using field emission scanning electron microscopy and Raman spectroscopy. The results obtained on sliding wear and friction behaviour of these nanocomposite coatings suggest that 50 wt.% of Ni in YSZ nanocomposite provides good wear resistance behaviour than that of other coatings. Such an improvement in tribomechanical and wear performance of the nanocomposite coating could be attributed to the optimum amount of Ni which promotes the formation of NiO from Ni due to the frictional heat between nanocomposite coating and the sliding counter body in wear track as confirmed by Raman analysis.

The work is devoted to the study of electrical properties (temperature dependences of conductivity, relative dielectric constant, dielectric loss tangent for various frequencies) of an aluminum oxide ceramic film deposited on a metal substrate. The film was created by an original method of electron beam evaporation of a nonconducting target consisting of a compressed alumina powder using a plasma electron source, which is able to reliably operate in the fore-vacuum pressure range (5–100 Pa). Such increased working gas pressure ensures the generation of a dense beam plasma near the target, which neutralizes the charging of a nonconducting target and thereby provides its effective melting and electron beam evaporation.

Because of its ability to change optical absorption dynamically by applied electric field, nickel oxide (NiO) is a promising anodic material in smart windows, which can improve energy conversion efficiency in construction buildings. Although many works have achieved high electrochromic performance with different method. The underlying mechanism is still not fully investigated. In this article, we prepared the NiO films with large specific surface area and high stability by electron beam evaporation. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to figure out the surface morphology and composition of as-deposited films. Afterwards, the electrochemical properties and optical performance of the prepared NiO films were investigated. On this basis, the origin of surface charge was fully analyzed by cyclic voltammetry and diffusion coefficient test. These experimental and theoretical results firmly confirm that both the surface reaction and capacitive effect bring about the excellent EC performance in NiO films. These results not only provide clear evidence about electrochemical kinetics in NiO films, but also offer some useful guidelines for the design of EC materials with higher performance and longer stability.

In our previous work, the detailed crystal structure, optical and electrical properties of evaporated CdS (hexagonal CdS) and chemical bath deposition CdS (cubic CdS) were discussed. The hexagonal CdS film is more suitable as the buffer layer for Sb2Se3 film solar cells compared with its cubic counterpart. However, in our experiments, the influence of high annealing temperature on hexagonal CdS is difficult to control. Moreover, hexagonal CdS is unsuitable for large-area industrial production of Sb2Se3 solar cells. In this study, an electron beam evaporation-prepared CdS buffer layer (hexagonal CdS) with high quality, uniformity and low-temperature treatment was introduced in Sb2Se3 thin film solar cells. The influence of different substrate temperatures during electron beam evaporation on the crystal structure, surface morphologies, and optical properties of CdS and Sb2Se3 films was investigated. The device performance improvement from 3.52% to 5.89% was obtained after the surface roughness of the CdS film and the heterojunction interface were optimised. Lastly, the efficiency of the Sb2Se3 solar cells was obtained to be 6.71% based on the structure of FTO/EB-CdS/Sb2Se3/MoO3/Au.

The preparation of large-area uniform continuous MoSe2 films is a challenge, which greatly limits its large-scale application. It is of great importance to control the preparation conditions to obtain a single-phase structure and excellent semiconductive properties. Herein, we report the preparation of thin MoSe2 films from Mo films using electron beam evaporation. The effects of the evaporation temperature, growth temperature, and growth time on the phase structure and stoichiometric ratio of thin MoSe2 films were investigated. It was concluded that the optimal preparation conditions of MoSe2 are a Se source temperature of 400℃, growth temperature of 600℃, and selenization time of 3 h. It was confirmed that thin MoSe2 films with a 2H phase prepared from a thin Mo film exhibit excellent semiconductor properties in a transistor device.

Tantalum pentoxide (Ta2O5) and ultraviolet reflective (UVR) multilayer films were deposited on quartz glass substrates by an electron beam evaporation system equipped with a hall ion source, respectively. The optical properties of Ta2O5 film and the UVR film under the vacuum ultraviolet irradiation were investigated. It is found that the mean transmittance of the Ta2O5 thin film decreased in the 300–500 nm region. The refractive index and extinction coefficient of the single layer increased during the range of 300–1 000 nm, with the variation rate of refractive index less than 1%, which is mainly due to the larger surface roughness and variation of the chemical state of Ta atoms on the surface caused by the irradiation. The mean reflectance of UVR film decreased from 96.5% to 95.4% during the range of 290–450 nm, indicating that the Ta2O5 and UVR films have excellent vacuum ultraviolet irradiation resistant properties.

—CoPt films obtained by electron beam evaporation with deposition of ten Co and Pt bilayers with a total thickness of 8 nm are experimentally investigated. The Hall effect and longitudinal magnetoresistance measurements were carried out with a temperature change from 8 to 300 K. At room temperature, using magnetic force microscopy, images of domain structures corresponding to different points of the magnetization reversal curve were obtained. The possibility of studying the Hall effect on artificially created domain structures formed by the local magnetic field of the probe of an atomic force microscope is demonstrated.

A typical high-efficiency solar cell device needs the best lattice matching between different constituent layers to mitigate the open-circuit voltage loss. In the present work, the physical properties of CdS thin films are investigated where films with 100 nm thickness were fabricated on the different types of substrates viz. soda–lime glass, indium-doped tin oxide (ITO)- and fluorine-doped tin oxide (FTO)-coated glass substrates, and silicon wafer using electron beam evaporation. The X-ray diffraction patterns confirmed that deposited thin films showed cubic phase and had (111) as predominant orientation where the structural parameters were observed to be varied with nature of substrates. The ohmic behaviour of the CdS films was disclosed by current–voltage characteristics, whereas the scanning electron microscopy micrograph revealed the uniform deposition of the CdS films with the presence of round-shaped grains. The elemental analysis confirmed the CdS films deposition where the Cd/S weight percentage ratio was changed with nature of substrates. The direct energy band gap was observed in the 1.63–2.50 eV range for the films grown on different substrates. The investigated properties of thin CdS layers demonstrated that the selection of substrate (in terms of nature) during device fabrication plays a crucial role.

Metallization is one of the pivotal steps in microelectronics and microelectromechanical device fabrication. An interesting challenge in metal cantilever fabrication is to produce free-standing beams with minimal deformation following the release. Such deformations are dictated by residual film stress and stress distribution uniformity across the substrate. In this work, aluminium thin film properties were tailored at room temperature by low energy argon plasma-assisted electron beam evaporation, using a hollow cathode end hall ion source. The influence of varying argon pressure for plasma assistance was investigated on residual film stress and stress distribution uniformity of 200 nm thick aluminium films. Improvement in film stress distribution across silicon substrate and densification of the film by ion-induced surface diffusion was observed for the deposition at room temperature. Cantilever beams were fabricated by dry etching technique; beam deformation was minimal for a film with uniform stress distribution across the substrate and low dislocation density, produced by plasma assistance.

This work investigates the effect of film thickness on the optical properties of dysprosium oxide (Dy2O3), fabricated onto sapphire (Al2O3) substrates using electron beam evaporation. The grazing incidence X-ray diffraction (GI-XRD) analysis showed that all films have a cubic crystalline structure. The average crystallite size was calculated using the Debye–Scherrer equation and was found to increase with the increasing film thickness. Similar behavior was observed in scanning electron microscopy and atomic force microscopy images. The optical properties of the grown layers such as the refractive index (n), extinction coefficient (k), and optical allowed f–f transitions of Dy3+were analyzed using spectroscopic ellipsometry (SE). The allowed f–f transitions of Dy3+was found to increase from 2.35 eV to 2.50 eV by decreasing the film thickness from 10 nm to 5 nm. UV–Vis spectrophotometry was used to examine the reflectance of Dy2O3 thin films. The results obtained in this study indicated that Dy2O3 with a 5 nm thickness is a better choice to grow an improved anti-reflective layer compared with the 10 nm layer.

Tantalum pentoxide (Ta2O5) has attracted intensive attention due to their excellent physicochemical properties. Ta2O5 films were synthesized via electron beam evaporation (EBE) and subsequently annealed at different temperatures ranging from 300 to 900 °C. X-ray diffraction (XRD) results show that amorphous Ta2O5 thin films form from 300 to 700 °C and then a phase transition to polycrystalline β-Ta2O5 films occurs since 900 °C. The surface morphology of the Ta2O5 films is uniform and smooth. The resulted Ta2O5 films exhibit excellent transmittance properties for wavelengths ranging from 300 to 1100 nm. The bandgap of the Ta2O5 films is broadened from 4.32 to 4.46 eV by annealing. The 900 °C polycrystalline film electrode has improved electrochemical stability, compared to the other amorphous counterparts.

The thin films of ITO/CdS and ITO/ZnO/CdS bi-layer have been fabricated and studied for structural, morphological, optical, and Urbach energy properties. ZnO thin films were coated onto ITO plated glass slides by a spin-coating method and CdS thin films by electron beam evaporation method. X-Ray Diffraction patterns of both ITO/CdS and ITO/ZnO/CdS thin films confirmed the hexagonal wurtzite structure of ZnO and hexagonal structure of CdS, respectively. AFM images show better uniformity and bigger grain size in the case of OTO/ZnO/CdS samples. Optical transmittance spectra show a slight redshift (~ 493 nm to ~ 505 nm) for the film ITO/ZnO/CdS compared to ITO/CdS. Urbach energy was calculated for all the samples to study the structural imperfections leading to the band tails. A decrease in Urbach energy is observed for ITO/ZnO/CdS compared to ITO/CdS. The obtained results indicate that the ITO/ZnO/CdS thin films are more suitable for optoelectronic devices compared to ITO/CdS films. The results obtained are discussed in detail and presented in this paper.

The possibility of using implantation of 20-keV He+ ions for modification of the domain structure and magnetic properties of CoPt films (formed by the electron-beam evaporation method) with different cobalt contents (Co0.45Pt0.55 and Co0.35Pt0.65) has been investigated. A decrease in the coercive field (narrowing of the hysteresis loop in the magnetic-field dependences of the Faraday angle and magnetization) with an increase in the He+ ion fluence from 2 × 1014 to 4 × 1014 cm–2 has been found for the irradiated CoPt samples of both compositions. The residual magnetization of the Co0.35Pt0.65 films coincides with the saturation magnetization, and a decrease in the residual magnetization is observed for Co0.45Pt0.55. It is shown by magnetic force microscopy that the largest number of round isolated domains (skyrmions) for the Co0.45Pt0.55 alloy are formed when the ion fluence increases to 3 × 1014 cm–2, while 360-degree domain walls (1D skyrmions) are observed along with round isolated domains for the Co0.35Pt0.65 films irradiated with a He+ fluence of 4 × 1014 cm–2. An analysis of CoPt films by Mandelstam–Brillouin spectroscopy revealed an increase in the shift between the Stokes and anti-Stokes components of the spectrum and a significant enhancement of the Dzyaloshinski–Moriya interaction in the irradiated samples. Model calculations performed using the SRIM program showed that the ion irradiation facilitates asymmetric mixing of Co and Pt atoms in CoPt films, which may underlie the mechanism of the observed effects of ion irradiation on their magnetic properties and domain structure.

Electromigration (EM) is considered as a serious issue that threatens the reliability of electronic packaging. For the long-term reliability of the application of pure silver thin films, it is important to investigate its EM effect; however, there are limited studies focused on this aspect. In this study, the EM of a silver thin film deposited on a glass substrate was examined at a current density of 8.89 × 105 A/cm2 and room temperature of 15 °C. During the EM test, the new phenomenon of the thin-thread silver structures with a unique direction was noted. To explain this, finite element analysis was applied to simulate the temperature and direction of the current flow. The effect of thermal and stress migration could be ignored in this experiment based on the temperature distribution results. The electron wind force played an important role in the formation of the thin-thread silver with nucleation structure following the direction and strength of the electron flow. By analyzing the failure location, melting was observed near the cathode since the generation of the thin-thread silver decreased the contact area for passing current. Finally, reducing the grain boundaries was proposed as an approach to improve the reliability of the pure silver sample, which is paramount for manufactures.

Metallization layers of aluminum, gold, or copper are shown to be protected from interactions with silicon substrates by thin boron layers grown by chemical-vapor deposition (CVD) at 450 °C. A 3-nm-thick B-layer was studied in detail. It formed the p+-anode region of PureB diodes that have a metallurgic junction depth of zero on n-type Si. The metals were deposited by electron-beam-assisted physical vapor deposition (EBPVD) at room temperature and annealed at temperatures up to 500 °C. In all cases, the B-layer was an effective material barrier between the metal and Si, as verified by practically unchanged PureB diode I–V characteristics and microscopy inspections of the deposited layers. For this result, it was required that the Si surface be clean before B-deposition. Any Si surface contamination was otherwise seen to impede a complete B-coverage giving, sometimes Schottky-like, current increases. For Au, room-temperature interactions with the Si through such pinholes in the B-layer were excessive after the 500 °C anneal.

Radiation fields occur in nuclear power plant primary circuits, and decontamination is needed before the permanent shutdown of a reactor. Radiation field reduction in the primary coolant system of water-cooled reactors can be achieved by using a decontamination solution. As part of this, the corrosion behavior and characterization of oxide layers formed on different kinds of metal should be examined. In this study, NiFe2O4 thin film was deposited on substrates of stainless steel, inconel and carbon steel via electron beam evaporation. The reaction between nickel ferrite and different metal ions results in varying compositions of oxide layers. The phase, structure and morphology of materials were confirmed by SEM, XRD and XPS analysis, and the magnetic properties of each deposited sample were observed by using vibrating sample magnetometer (VSM). The characteristics of the surface-coated metals are the main focus of this work.

The present work includes the fabrication of Mg0.4Ti0.6O2 thin film (TF) based Metal-oxide–semiconductor (MOS) capacitor on (1 0 0) n-type GaAs substrates by electron beam evaporation technique. The thickness of the thin film alloy is found to be about 300 nm measured from Field emission gun-scanning electron microscope (FEG-SEM) data. The pore volume, surface roughness and grain size of the thin film samples are calculated from non-contact atomic force microscopy (NC-AFM) images. Experimental as well as analytical studies have been carried out to determine the bandgap and defect level transition of the material. The band-to-band transition of the Mg0.4Ti0.6O2 sample is calculated to be at ~ 5.2 eV. The as prepared sample shows tetragonal crystal structure. Presence of anatase phase of TiO2 in the TF material is confirmed through XRD (X-ray diffraction) investigation. Current (I) – Voltage (V) characteristics of the Mg0.4Ti0.6O2 Schottky devices reveal that the leakage current at −1 V is 8.1 × 10-4 A.

Silver (Ag) films with different nanostructures were prepared by electron beam evaporation and characterized by spectroscopic ellipsometry in combination with X-ray diffraction and field emission s...

In this work, the blade-type field emission cathodes (BFECs) of original construction have been developed and produced. As the basis of the cathodes the (110)-cut silicon wafers were used. On the upper surface of Si substrate the parallel grooves of the 20 μm width and 50 μm depth of 1.7 mm in length were etched in a concentrated aqueous 44% KOH solution. As a result the parallel Si walls of the rectangular shape were created, which after imparting them a wedge shape form were used as a pedestals for supporting of emitting graphite blades, obtained by the electron beam evaporation of graphite. The blades were sharpened to the thickness not exceeding 10 nm. It was shown that our BFECs can operate at field emission current up to 6 mA, depending on the sharpness of a blade. It was found that the cathodes, which had previously worked on low currents, then showed high limiting currents, in comparison with the cathodes, which were initially forced to work on extreme emission currents.

In the present study, pure zinc sulfide, zinc sulfide annealed at 500 °C, and zinc sulfide-europium oxide nanocomposite were deposited on a silicon substrate by the electron beam deposition method and their structural and optical properties and detection behavior were investigated. Zinc sulfide nanoparticles were synthesized by chemical deposition and annealed at 500 °C. Their structural and phase properties were studied by X-ray diffraction (XRD), indicating formation of wurtzite phase on the zinc sulfide structure. Europium oxide was added to the composite as a reinforcing phase at 5 wt% by the chemical deposition method. The XRD pattern demonstrated that there was a good intensity of the europium oxide peaks along the zinc sulfide peaks in the nanocomposite. Scanning electron microscopy showed that the zinc sulfide layers deposited by the electron beam deposition method had a good uniformity and that the europium oxide particles were presented in the layers with good dispersion. The energy dispersive spectroscopy showed that the stoichiometry of the zinc sulfide deposited on the silicon substrate did not change with the electron beam deposition method and confirmed the presence of europium oxide in the layers. Photoluminescence spectroscopy results showed that with the addition of europium oxide to the zinc sulfide, the intensity of the peaks increased compared to pure zinc sulfide and annealed zinc sulfide at 500 °C, which showed an increase in the rate of electron-hole generation. This increase in electron-hole generation was also demonstrated in the optoelectrical properties of the fabricated photodetectors. The sensitivity of the detector under UV illumination for pure zinc sulfide and annealed sample at 500 °C was 10.30 and 15.29, respectively. But for the sample containing europium oxide, the sensitivity increased to 42.76.

Ti–6Al–4V alloy was borided by using a two-stage boriding process. In the first stage, boron atoms accumulated on Ti–6Al–4V alloy samples via electron beam evaporation technique. The second stage included annealing of samples after boron deposition at various temperatures in order to achieve boride layer with high hardness and adherence. After the boriding treatment, phases formed on the surface of the Ti–6Al–4V alloy were identified by X-ray diffraction technique. The microstructure and thickness of boride layers were examined by scanning electron microscope. Microstructural analyses indicated that surface structure of borided samples comprised of TiB2 layer on the top and TiB whiskers towards the substrate. It was revealed that boriding by electron beam evaporation technique resulted in formation of a hard and adhered surface structure after annealing especially at 950°C for 24 h. Microhardness measurements showed that boride layer on Ti–6Al–4V has mean hardness value of about 1937 HV. Boriding at 950°C for 24 h brought about an improvement in wear resistance of Ti–6Al–4V alloy. The borided surface exhibited higher wear resistance along with higher coefficient of friction as compared to as-received one.

WO3 films with thicknesses between 550 and 853 nm were deposited on glass substrates using the electron beam evaporation method at room temperature. The microstructures and surface roughness of the films were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). It was observed that the crystalline structure of the WO3 thin films significantly changes from the amorphous to crystalline states with a crystalline texture, and the mosaicity and grain size dependent on the film thickness. The transmittance spectra of the obtained WO3 films were measured in the range from 340 to 850 nm, and the Swanepoel method was used to determine the refractive indices and the thicknesses of the WO3 films. The obtained optical functions reveal the highly homogeneous structure of the films.

In this paper, ZrO2 is deposited on a polyethylene-based separator via electron beam evaporation method. The analyses reveal that the application of the ceramic-based coating enhances the electrolyte uptake capability from 79 to 135% and the ionic conductivity from 7.1 x 10(-4) to 7.5 x 10(-4) S/cm. Linear sweep voltammetry tests show the superior electrochemical stability in the coated separator up to 5.5 V. This study shows that with the thin ZrO2 coating, the separator maintains its structure plus the existence of ZrO2 has an essential impact on electrolyte decomposition, SEI layer formation, and safety of the separator. WOS:000591982300001 2-s2.0-85096444944

A normally OFF hydrogen-terminated diamond (H-terminated diamond) field-effect transistor (FET) has been successfully achieved with Ti/TiO x gate materials. A 5-nm Ti film was deposited on H-terminated diamond by electron beam evaporation technique and then it was thermally oxidized in air at 120 °C for 10 h to form Ti/TiO x , which was confirmed by X-ray photoelectron spectroscopy. The threshold voltage of H-terminated diamond FET is −0.14 V at ${V}_{DS}$ of −8 V, indicating a normally OFF operation. The normally OFF property could be attributed to the difference of work difference between Ti and H-terminated diamond, which may deplete the hole carriers in H-terminated diamond 2-D hole gas (2DHG) conduction channel. The maximum mobility of H-terminated diamond FET is 313 cm2/Vs at ${V}_{GS}$ of −0.2 V. And, the fixed negative charge density is $3.37 \times 10 _{11}$ cm−2. The results demonstrate that Ti/TiO x H-terminated diamond FET is a good solution to fabricate normally OFF device with a simple fabrication process, undamaged 2DHG channel, and uncontaminated interface between Ti and TiO x gate materials, which may promote the development of normally OFF H-terminated diamond FET.

CdTe and 1–5 wt% molybdenum-doped CdTe materials were prepared by ball milling method. Then the ball-milled samples were deposited on a glass substrate at room temperature by an electron beam evaporation method. The structural, optical, morphological, electrical, and photo-response properties of CdTe and Mo-doped CdTe (CdTe:Mo) samples were investigated. The prepared samples exhibit a cubic structure of CdTe. X-ray diffraction pattern (XRD) showed that the deposited films belong to the cubic structure with a preferential growth along (111) plane. The peak shift in the lower side of 2θ was observed due to incorporation of Mo into the CdTe matrix. Surface morphology of the prepared CdTe and CdTe:Mo ball-milled samples showed the formation of various agglomerated structures. Scanning electron microscope images depicted the formation of high dense agglomerated grains on the film surface with varying sizes as a function of Mo concentration. The optical bandgap was increased from 1.38 to 1.54 eV with raising the Mo concentration in CdTe films. Enhanced optical absorption coefficients (~ 17 × 104 cm−1) were observed for 3 and 4 wt% Mo doped CdTe thin films. Hall measurement studies revealed that Mo doped CdTe (3 wt%) film possesses a low resistivity of 34 × 103 Ω cm. The CdTe and CdTe:Mo films exhibit p-type conduction. The high photo-response of 0.088 AW−1 is observed for 3 wt% Mo-doped CdTe thin film.

The introduction of graphene (Gr) with high thermal conductivity between GaAs and metal electrode can reduce the internal temperature rise and thermal stress accumulation of high-power chips, such as photoconductive switches, protect the contact electrode, and improve the device stability. Meanwhile, the introduction of graphene has the potential to decrease the interface contact resistance. It is valuable to study the effect of graphene on the contact characteristics of the metal–semiconductor interface. The metallic composite Ni/Ge/Au/Ni/Au was obtained by electron beam evaporation, and the graphene was grown by CVD. The current–voltage ( ${I}$ – ${V}$ ) characteristics of the devices over a high-temperature range 300 K–420 K were measured by a semiconductor parameter analyzer. The Schottky barrier properties of metal/semi-insulating GaAs (M/SI-GaAs) with and without graphene interlayer were analyzed by some analysis techniques, such as forward ${I}$ – ${V}$ and Norde’s methods. It was observed that the barrier heights (BHs) were inhomogeneous in the high-temperature range. The mean BHs were extracted by the experimental BH versus 1/T. We found that the homogeneous BH of M/Gr/SI-GaAs was lower that of M/SI-GaAs. It is helpful to improve the performance of semiconductor devices, as we realized the specific contact resistivity lower by two orders of magnitudes via graphene insertion.