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Evolution of structural and magnetic properties in a nickel/chromium (Ni/Cr) multilayer, as a function of different annealing temperatures was investigated. The Ni/Cr multilayer of nominal structure [Cr (50 Å)/Ni (50 Å)]×10/Cr (30 Å) was grown on a Si substrate by radio frequency ion beam sputtering at room temperature. X-ray diffraction, X-ray reflectometry, atomic force microscopy and crossectional scanning electron microscopy were employed for the complete structural characterization of the multilayer whereas superconducting quantum interference device vibration sample magnetometer was used for the bulk magnetisation study. The effect of in-situ and ex-situ annealing on overall structural property of the multilayer also reported in present work. From in-situ X-ray reflectometry (50–400 °C), 300 °C was detected as the optimum temperature for improved structural properties of the Ni/Cr multilayer. Initiation of alloying in the multilayer sample was noticed at 350 °C. The multilayer found to exhibit polycrystalline nature observed by X-ray diffraction. Total thickness of the multilayer system was confirmed by crossectional scanning electron microscopy and in well agreement with X-ray reflectivity results. The Ni/Cr sample found to exhibit soft ferromagnetic behaviour after annealing at 300 °C and 400 °C. However the net magnetic moment reduced upon annealing at higher temperature (400 °C).

In the pristine as well as the doped BiFeO3 samples, ferroelectric domains show switching behavior. The regions marked by yellow color loops show either 71° or 109°-domains, whereas those marked by white loops are 180°-domains.

Discovery of two-dimensional (2D) topological insulators (TIs) demonstrates tremendous potential in the field of thermoelectric since the last decade. Here, we have synthesized 2D TI, Sb2Te3 of various thicknesses in the range 65–400 nm using mechanical exfoliation and studied temperature coefficient in the range 100–300 K using micro-Raman spectroscopy. The temperature dependence of the peak position and line width of phonon modes have been analyzed to determine the temperature coefficient, which is found to be in the order of 10–2 cm−1/K, and it decreases with a decrease in Sb2Te3 thickness. Such low-temperature coefficient would favor to achieve a high figure of merit (ZT) and pave the way to use this material as an excellent candidate for thermoelectric materials. We have estimated the thermal conductivity of Sb2Te3 flake with the thickness of 115 nm supported on 300-nm SiO2/Si substrate which is found to be ~ 10 W/m–K. The slightly higher thermal conductivity value suggests that the supporting substrate significantly affects the heat dissipation of the Sb2Te3 flake.

Wrinkles significantly influence the physical properties of layered 2D materials, including graphene. In this work, we examined thermal transport across wrinkles in vertical assemblies of few-layer graphene crystallites using the Raman optothermal technique supported by finite-element analysis simulations. A high density of randomly oriented uniaxial wrinkles were frequently observed in the few-layer graphene stacks which were grown by chemical vapor deposition and transferred on Si/SiO2 substrates. The thermal conductivity of unwrinkled regions was measured to be, κ ∼ 165 W m−1 K−1. Measurements at the wrinkle sites revealed local enhancement of thermal conductivity, with κ ∼ 225 W m−1 K−1. Furthermore, the total interface conductance of wrinkled regions decreased by more than an order of magnitude compared to that of the unwrinkled regions. The physical origin of these observations is discussed based on wrinkle mediated decoupling of the stacked crystallites and partial suspension of the film. Wrinkles are ubiquitous in layered 2D materials, and our work demonstrates their strong influence on thermal transport.

High-performance solar-blind photo-detection using highly transparent CuO nanostructures (with a bandgap of 4.15 eV) has been demonstrated. The device shows the dark current as low as 0.2 nA (−10 V applied bias) and no signature of breakdown even at a bias up to ±175 V. The device has shown record photo-sensitivity of 610, photo-responsivity of 14.02 A/W and photo-detectivity of $3.59\times 10 ^{13}$ cmHz 1/2W−1 in the UV-C region. The ratio of photo-responsivities at 210 nm and 500 nm i.e. R210/R500 was found to be $5.05\times 10 ^{4}$ . Additionally, the device has shown external quantum efficiency of ~5900 % at 210 nm excitation. This letter will establish CuO as one of the most promising ultra-wide bandgap semiconductors for cost-effective solar blind photo-detection.

We propose a method for substrate surface texturing with shallow micro structures (such as cylinders) made up of cross-linked SU8 2005 photoresist on glass substrates for conformal growth of thin films of functional materials. In this work, the textured substrates were used for the growth of antimony selenide (Sb2Se3) solar absorber and its properties were studied in comparison with films on plain glass substrates. Cross-linked SU8 2005 structures, i.e., an array of equally spaced cylinders having the dimensions of 100 µm/70 µm/40 µm diameter and 5 µm height, were introduced over an area of 20 mm × 20 mm on glass substrates via optical lithography process. Thin films of Sb2Se3 were grown above the textured surface using e-beam evaporation covering the glass-like resist structures underneath. Optical microscopy, scanning electron microscope (SEM) and optical profiler analyses confirm the morphological integrity of the Sb2Se3 absorber layer grown on textured substrates. Raman spectra were collected on plain and textured samples to probe the structural uniformity. The optical absorbance data of Sb2Se3 thin films grown on plain and periodically textured glass substrates were investigated using UV–Vis-NIR spectroscopy to study the effects of substrate texturing.

Gold nanoparticles (AuNPs) and gold nanoclusters (AuNCs) are gaining interest in medical diagnosis and therapy as they are bio-compatible and are easy to functionalize. Their interaction with radiofrequency (RF) field for hyperthermia treatment is ambiguous and needs further investigation. A systematic study of the absorption of capacitive RF field by AuNPs and AuNCs dispersed in phosphate-buffered saline (PBS) is reported here in tissue mimicking phantom. The stability of AuNPs and AuNCs dispersed in PBS was confirmed for a range of pH and temperature expected during RF hyperthermia treatment. Colloidal gold solutions with AuNPs (10 nm) and AuNCs (2 nm), and control, i.e. PBS without nanogold, were loaded individually in 3 ml wells in a tissue phantom. Phantom heating was carried out using 27 MHz short-wave diathermy equipment at 200 and 400 W for control and colloidal gold solutions. Experiments were conducted for colloidal gold at varying gold concentrations (10-100 µg/ml). Temperature rise measured in the phantom wells did not show dependence on the concentration and size of the AuNPs. Furthermore, temperature rise recorded in the control was comparable with the measurements recorded in both nanogold suspensions (2, 10 nm). Dielectric property measurements of control and colloidal gold showed3% difference in electrical conductivity between the control and colloidal gold for both nanoparticle sizes. From the measurements, it is concluded that AuNPs and AuNCs do not enhance the absorption of RF-capacitive field and power absorption observed in the biological medium is due to the ions present in the medium.

We report synthesis of Copper Zinc Tin Sulfide (CZTS) thin films using sequential evaporation technique. The as-deposited films were subjected to various sulfurization temperatures ranging from 520 °C to 640 °C. This paper presents a detailed analysis of temperature dependent phase and defect formation in Cu-rich off-stoichiometric CZTS thin films. CZTS thin films moved from F-type to C-type with decreasing Cu/Zn disorder and defect concentration with increasing sulfurization temperature. The resulting films showed less off-stoichiometry in contrast to initial choice of intended off-stoichiometry exhibiting the structural flexibility within the compositional limits. Despite being off-stoichiometric, all the samples exhibited the tetragonal CZTS phase with preferred orientations. Raman analysis showed the disappearance and reappearance of secondary phases with increasing sulfurization temperature. EDS analysis suggested that composition of the films moved towards better stoichiometry till 580 °C before deteriorating again. Composition and lattice parameter values suggested Cu-rich off-stoichiometric nature of sulfurized CZTS thin films. AFM study showed dependence of roughness with sulfurization temperature. Band gap was obtained in the range of 1.28 eV to 1.48 eV from UV–Vis spectroscopy measurement. PL analysis revealed the asymmetric shape and blue shift of the peaks. Band-to-tail recombination becomes pronounced with increase in sulfurization temperature. XPS analysis showed elements are in expected oxidation states.

Substitution of alkali earth metal ion of Sr2+, in the Pb2+ site of Pb(Mg1/3Nb2/3)O3–PbTiO3 is expected to induce functional modulations in the system. Doping of 4 at.% of Sr2+ in 0.68PMN-0.32PT was carried out to lower the transition temperature, and to investigate the intended ferroelectric and dielectric variations. Excellent relaxor property was observed in the doped sample without appreciable reduction in remnant polarization. Doping with Sr2+ led to a reduction in transition temperature from 165 °C to 117 °C. Doped sample exhibited remnant polarization Pr = 16.2 μC/cm2, Squareness factor (Rsq) = 1.05 and Relaxor exponent (γ) around 2. Modulation in the functional response was exhibited by the doped composition, having low transition temperature, and its prospect in electrocaloric applications was analyzed.

Persistent photoconductivity (PPC) in solution-processed pristine CuO and Au coated CuO thin films have been studied. Long-lasting PPC has been observed in Au coated CuO thin films with stable current levels even for 7 days. For the first time, long-lasting PPC effect in Au/CuO has been utilized for non-volatile optical memory. We have established both the SET and RESET processes using optical excitation. For the SET process, deep UV illumination ( $\lambda _{\mathrm {ex}}=254$ nm) was used while for the RESET, NIR ( $\lambda _{\mathrm {ex}}=800$ nm) excitation was used. In addition to the optical reset, low-temperature annealing (50 °C) was utilized for resetting the device. PPC effect in Au/CuO films has enormous possibility for next-generation commercial optical memory devices and neuromorphic computing.

In this study we investigated the ferroelectric and piezoelectric behaviour of co-sintered magnetoelectric composite fabricated by tape-casting method using Pb(1-x-3y/2)SrxLay(Zrz,Ti(1-z))O3 piezoelectric ceramic with x = 0.06, y = 0.03, z = 0.56 (PSLZT) multilayer and Ni0.6Zn0.4Fe2O4 (NZFO). PSLZT and NZFO powders were prepared by solid state reaction method and respective thick films were fabricated by tape casting method. PSLZT multilayer with Pt inner electrodes were laminated with NZFO and co-sintered at 1060 °C for 2 h to obtain delamination free layered composite. Scanning electron microscopy was employed to analyse the microstructure and interface of the co-sintered multilayer which are crucial for elastic coupling. Micrographs recorded across the cross section of the composites revealed insignificant interdiffusion between the phases. Individual piezoelectric multilayer and magnetoelectric composites were analysed for their ferroelectric behaviour. Piezo Force Microscopy (PFM) and Magnetic Force Microscopy (MFM) were utilized to study the ferroelectric domains and magnetic domains on top surface of PSLZT multilayer and NZFO, respectively in composite structure. Ferroelectric behaviour of PSLZT multilayer - NZFO composite was recorded and compared with 3 layered PSLZT. The values of remanent polarization were found to be 50.6 μC/cm2 and 55 μm/cm2 whereas capacitance at 1 Hz found to be 31.5 nF and 28.9 nF for PSLZT multilayer and PSLZT multilayer – NZFO composite respectively. Piezoelectric coefficient of PSLZT multilayer was found to be 980–1030 pC/N whereas for PSLZT multilayer – NZFO composites it was 1050–1150 pC/N. Magnetoelectric coefficient of 150 mV/cm.Oe was obtained for the same composite structure.

We have made an attempt to fabricate free standing warpage free PZT thick films of 100 µm thickness by tape casting method. The poly crystalline nature and nanoscale polarization switching of free ...

We demonstrate high performance broadband UV-to-NIR detection, which is a critical issue associated with ZnO-based photodetectors. The as-synthesized ZnO-ZnCr2O4 nanowalls were first time utilized for broadband, i.e., 250–850 nm photo-detection (both in front and back illumination configurations). The dark current was found to be as low as 0.12 nA. The device has shown peak sensitivity for the UV region ( $\lambda _{\mathrm {ex}}= {350}$ nm) with the photo-sensitivity of $\sim 1.28\times 10^{5}$ , photo-responsivity of 5.49 AW−1, photo-detectivity of $1.91\times 10^{13}$ cmHz1/2W−1, linear dynamic range of 82 dB, and external quantum efficiency of 1900%. In addition, the white light emission (CIE coordinates of 0.32 and 0.34) was also observed in the ZnO-ZnCr2O4 nanowalls. This letter will open new directions in oxide semiconductors-based optoelectronic devices.

We report on the fabrication of ZnO and Zn0.9Mg0.1O microrods using nanoparticle assisted pulsed laser deposition (NAPLD). Micro-photoluminescence studies reveal that Zn0.9Mg0.1O microrods exhibited a blue shift in the ultraviolet (UV) emission relative to unintentionally doped ZnO that was attributed to the increase in bandgap due to Mg doping. High-resolution micro-photoluminescence clearly indicated the presence of whispering gallery modes (WGMs) for both ZnO and Zn0.9Mg0.1O. Transverse electric (TE) and transverse magnetic (TM) optical WGMs were identified using the existing plane-wave model. The observation of lower order WGM modes in Zn0.9Mg0.1O microrods may be of great interest for future UV WGM lasing.

Polymer/lead zirconate titanate {[Pb(Zrx, Ti1-x)O3], PZT, x = 0.40} flexible composite films are prepared by solvent evaporation technique. Carbon tape used as a top and bottom electrodes for fabricating flexible PZT composite films. The phase purity and functional groups of PZT and polymer humps are confirmed by XRD and FTIR respectively. XPS analysis showed that PMMA contains carbon (C) and oxygen (O). Carbon (C), oxygen (O), lead (Pb), zirconium (Zr) and titanium (Ti) are present in PZT/PMMA composite films. The chemical states of Pb, Zr and Ti ions are 2+, 4+ and 4+ respectively confirmed by XPS. The higher forefinger bending motion of the film is found to reveal greater output voltage (5.2 V) than the output voltage (1.6 V) for slight bending motion of the forefinger. Therefore, based on the results human mechanical forces induce compressive stress on PZTs ferroelectric based composite films and are excellent candidate for energy harvester.

Cubic silicon carbide (3C-SiC) films were grown by pulsed laser deposition (PLD) on magnesium oxide [MgO (100)] substrates at a substrate temperature of 800°C. Besides, p-type SiC was prepared by laser assisted doping of Al in the PLD grown intrinsic SiC film. The SiC phases, in the grown thin films, were confirmed by x-ray diffraction (XRD), Si–C bond structure is identified by Fourier-transform infrared spectroscopy spectrum analysis. Measurements based on the XRD and Raman scattering techniques confirmed improvement in crystallization of 3C-SiC thin films with the laser assisted doping. The studies on I–V characteristics by two probe technique, elemental analysis by energy dispersion spectrum, binding energy by x-ray photoelectron spectroscopy and carrier concentration by Hall effect, ensured Al doping in SiC thin film. From the UV–visible NIR spectroscopic analysis, the optical bandgap of the PLD grown 3C-SiC was obtained. Numerical analysis of temperature and carrier concentration distribution is simulated to understand the mechanism of laser assisted doping.

We explored the time dependence of the nanoscale domain relaxation mechanism in epitaxial K

Highly transparent (Transmittance >90%), solution-processed thin films of CuO with a direct bandgap of 3.87 eV were first time utilized for solar blind photo-detection. The CuO thin-film-based photodetector has shown very large DUV/Vis. rejection ratio of ~5430. The device has shown photo-responsivity value of 7.77 AW $^{-\textsf {1}}$ and photo-detectivity of $3.08\times 10^{\textsf {11}}$ cm $\cdot $ Hz $^{\textsf {1/2}}\cdot \text{W}^{-\textsf {1}}$ . Interestingly, the device has shown persistent photoconductivity with a retention time of several days. In order to use the device for optical memory, the reset mechanism has been successfully demonstrated by annealing the device at 50 °C. The developed solution processed, highly transparent, solar-blind photodetector has immense potential for next-generation cost-effective optoelectronic devices.

The local electrical conductivity and impurity band evolution in superconducting nanocrystalline boron doped diamond (BNCD) film are investigated using conducting atomic force microscopy (C-AFM) and X-ray absorption spectroscopy (XAS). C-AFM has been employed to investigate the local conductivity of superconducting BNCD with T c = 4.3 K and upper critical field H c 2 (0) = 5.2 T. A high local electrical heterogeneity of the BNCD film as evidenced from the C-AFM profile points to the uneven boron uptake during the process of doping. C-AFM also revealed that grain boundaries are the highly conducting regions, possibly, due to the presence of p-type trans-polyacetylene along with the C C and C H bonds in the grain boundaries. From the in-depth XPS profiling of the B 1s spectra we confirmed the macroscopic uniformity of the boron concentration across the depth of BNCD layers. X-ray absorption spectroscopy (XAS) measurements near B K-edge and C K-edge showed formation of in-gap states as a result of heavy boron doping. Near C K-edge, bandgap states at 282.8 eV and 284.1 eV are found which are responsible for superconductivity in the BNCD film. This work explores the non-uniform boron doping and its effect on the conduction band structure of a superconducting BNCD film.

We demonstrate low power continuous wave, red and NIR exciton lasing with FWHM of 1 nm, quality factor of 680 and threshold power of 100 μW in ZnO-ZnCr2O4 nanowalls. The NIR lasing was enabled by integrating ZnO with ZnCr2O4. Moreover, wavelength selective photoluminescence (tuning from UV to NIR) and enhanced two-photon emission were also observed in ZnO-ZnCr2O4 nanowalls. The exciton-exciton scattering can be attributed to the observation of exciton lasing at low temperature (

We find direct evidence of stain driven phase transition from face centered cubic (FCC) to body centered cubic (BCC) structure in radio frequency (RF) sputtered molybdenum (Mo) thin films as a function of deposition parameters. The structural, microstructural and electrical behavior of the Mo films are greatly influenced by the sputtering parameters i.e. RF power and argon (Ar) pressure. Although Mo is reported to be stable in BCC structure, our findings reveal that at certain deposition conditions, Mo films crystallize in FCC structure with good adherence to glass substrate; high resistance and strain (~214 Ω/□, ~3.43%). On varying sputtering parameters, strain releases and Mo films crystallize in mixed phase (FCC and BCC) which turns into pure BCC phase on further optimization. The stable BCC structured films have low resistance and strain (~1.29 Ω/□, ~−0.23%). We deposited bi-layer of Mo, where the bottom layer has strong adhesion to the substrate and top layer has low resistance (~0.81 Ω/□). The Mo film that crystallized in pure BCC form showed a strain value of −0.09% (compressive).

BaTi1-xSnxO3 of compositions x = 0.07, 0.08, 0.09, 0.10 and 0.11 are synthesized to study their piezoelectric and impedance characteristics. The studies revealed that the composition x = 0.08 exhibits the maximum piezoelectric coefficient (d33 = 296 pC/N) and remnant polarization (Pr = 6.92 μC/cm2) values. The impedance analysis showed that the depressed semi-circular arc observed in the Nyquist’s plots gave evidence for the existence of non-Debye type relaxation behavior in the compounds. The impedance studies suggested a possible correlation between the d33 and microstructural properties. The activation energies extracted from ac conductivity plots strongly indicate the existence of defect dipole assisted conductivity mechanism in the samples. Notably, the samples displayed positive temperature coefficient of resistance (PTCR) just above their ferroelectric transition. The frequency dependent ac conductivity follows the Jonscher’s universal power law. The dominant conduction mechanism in the samples is determined to be the small polaron hopping mechanism.

Poly(vinylidine fluoride) (PVDF) is a semicrystalline polymer which is known to exist in several polymorphic phases, namely, α, β, and γ. Each one of these polymorphic phases is characterized by unique features such as spherulite formation in the case of the α and γ phases and the presence of large piezoelectric and ferroelectric activity in the β phase. Despite being widely used as thin coatings in sensors, lack of reports on nanomechanical properties suggests that investigation of mechanical properties of PVDF, let alone those of its polymorphic phases, seems to have evaded the sight of the research community. Herein, we report the nanomechanical properties of the α, β, and γ phases of PVDF. The modulus and hardness values were evaluated from nanoindentation experiments; it was found that the electroactive β phase is the softest among the three polymorphic phases. This result was further confirmed by scratch experiments. We have attempted to establish a correlation between the microstructure and nanomechanical properties of these phases. This work sheds light on the mechanisms responsible for the observed mechanical behavior and the role of tie molecules and amorphous content in providing flexibility to the polymer.

Asymmetric supercapacitors based on aqueous and solid-state electrolytes are useful for a variety of applications. The birnessite δ-MnO2 is one of the efficient materials from the MnOx family characterized by large interlayer distance (∼7.3 A) and high theoretical specific capacitance (∼1370 F g−1). However the main concern which hinders its usage for practical applications is its low electronic conductivity (∼10−6 S cm−1). There are different means to enhance the conductivity and in the present studies, two simultaneous methods viz; a method of synthesis of nano-flakes along with Zn-doping in δ-MnO2 is implemented. A specific capacitance of ∼466 F g−1 at a current density of 0.5 A g−1 is obtained for an optimum Zn doping concentration of 1 mol% which is almost two times more than the corresponding pristine one. Both aqueous and solid-state asymmetric supercapacitor devices are fabricated using Zn doped δ-MnO2 as electrode material which can be easily scalable to industrial level. A lab-scale demonstration prototype is constructed which essentially validated the charging of solid-state supercapacitor using battery and allowing the supercapacitor to discharge through a red-LED by means of a two-way switch.

By optimizing laser raster scanning conditions and controlling PbO evaporation, we have grown high quality large area PbZr.52Ti.48O3 (PZT) thin films using custom-built off-axis pulsed laser deposition (PLD) technique. The realization of high quality PZT thin films over a large area with uniform polarization is a challenging task due to the formation of non-ferroelectric or pyrochlore like PbTi3O7 phases at the processing temperature ( > 600 ° C ). Our results show the polycrystalline nature of the sample with a uniform chemical surface composition. The macroscopic level of polarization mapping shows excellent saturated P-E loops with a narrow variation (6%) of the remnant polarization (2Pr) across the large area thin films. A comparative study of macroscopic and nanoscale level of mapping of polarization switching are performed, to demonstrate the existence of stoichiometry ferroelectric PZT thin films over a large area. The achievement of high quality large area PZT thin films with uniform polarization might be used for under-water SONAR devices and in power harvesting.

Pulsed laser deposited MgxZn1 − xO films grown on sapphire substrates exhibited wurtzite hexagonal structure at lower Mg concentrations (x

Mn2O3 is a pseudocapacitive material and a valuable member of the MnOx family with a theoretical specific capacitance of ~600 Fg−1. Despite its good material properties, low electronic conductivity (10−5 Scm−1) limits their usage in supercapacitor industries especially in high rate applications. To improve the material properties, Mn2O3 (NFs) composited with ZnMn2O4 (ZMO) were synthesised using a cost-effective electrospinning method and the resultant nanofibers were characterised by larger surface active reaction sites and enhanced charge-transfer kinetics. Phase fraction of ZMO in Mn2O3 NFs, for getting maximum specific capacitance was optimised as 1 wt%. About 98% of the capacitance (82 Fg−1) was retained after 3000 cycles at a higher current density of 20 Ag−1. Mn2O3 NFs and their composites are susceptible to electrochemical activation during charge-discharge cycles and cycling-protocol for maximum specific capacitance was found out. Nanofibers and their composites synthesised via electrospinning gives substantial hope in fiber based supercapacitor technology. Keywords: Electrospinning, Mn2O3, ZnMn2O4, Composites, Synergistic effect, Supercapacitors

Maximizing the use of cutting tool inserts and effectively utilizing them in the automated manufacturing process is critical to reducing machine down time and improving part quality. Early removal of tooling inserts can lead to less productivity and increased costs. Utilization of tooling inserts beyond its stipulated life time can cause dimensional inaccuracies and undesirable surface deterioration. Optimizing the cutting tool insert life will require an appropriate method for finding out remaining useful life of tooling inserts based on respective machining conditions. In this present work, acoustic signals and vibration signals were acquired during machining to monitor the tool failure. The change in signal variations in acoustic emission and vibration signals were correlated to the corresponding tool wear during machining. In this regard, machining experiments were performed on AA2124/25%/SiCp material using four different CVD Diamond coated tungsten carbide cutting tools (MCD-Microcrystalline diamond coating, NCD-Nano-crystalline diamond coating, BDD-Boron doped diamond coating, BMTN-Boron doped graded layer diamond coating) at an suitable cutting conditions. The results indicated that burst type AE signals observed in MCD and NCD coated tools correlated to chip entanglement, edge chipping, and the corresponding vibration analysis shows a similar increase in amplitude in the final cutting pass. However, there was no abnormality seen in BDD and BMTN coated tools signal variation which indicates least tool wear.

In this study, the effect of annealing ambient on SnO 2 thin film transistors (TFTs) is presented. Phase pure SnO 2 films have been deposited using solution processed spin coating technique with SnCl 2 as the precursor material. The films are annealed at 500 °C for 1 h in different annealing ambient conditions with varying N 2 :O 2 ratio. Top gate, bottom contact TFTs have been fabricated with SnO 2 as the channel layer, silicon as the gate, silicon dioxide as the dielectric and gold as the contact material. XRD patterns reveal the amorphous nature of films. AFM image shows that the spin coated films are pin-hole free with extremely smooth surface morphology. PL and XPS measurements reveal that with increase in N 2 % during annealing, the defects in the films increase. However, with increase in nitrogen concentration, the device performance improves, the threshold voltage shifts towards lower values and mobility increases, but very high N 2 % is not suitable for device operation, a 70% N 2 + 30% O 2 annealing ambient is found to be suitable with devices showing saturation mobility of 0.23 cm 2 V −1 s −1 and threshold voltage of 6.8 V and on/off ratio of 10 6 .

We report on the growth of ZnO nanostructures in different gas ambient (Ar and N 2 ) using pulsed laser deposition technique. Despite the similar growth temperature, use of N 2 ambient gas resulted in well-aligned nanorods with flat surface at the tip, whereas, nanorods grown with Ar ambient exhibited tapered tips. The Nanorods grown under N 2 ambient exhibited additional Raman modes corresponding to N induced zinc interstitials. The nanorods are c-axis oriented and highly epitaxial in nature. Photoluminescence spectroscopy reveals that the UV emission can be significantly enhanced by 10 times for the nanorods grown under Ar ambient. The enhanced UV emission is attributed to the reduction in polarization electric field along the c-axis. n -ZnO nanorods/p-Si heterojunction showed rectifying I–V characteristics with a turn of voltage of 3.4 V.

In this study we made an attempt to fabricate magnetoelectric composite of magnetostrictive NZFO layer on piezoelectric PSLZT multilayer by co-sintering them directly. Microstructural analyses of t...

Synthesis of single phase (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 ceramics with enhanced electrical response was achieved by excluding excess PbO from the precursor, making them suitable for device applications. This report is an inquiry into the effect of high temperature stabilization used for the realization of single phase PMN-PT ceramics on the electrical properties exhibited by the compositions in the morphotropic phase boundary. Functional response exhibited by the high temperature stabilized ceramics is correlated with the structural fluctuations in the morphotropic phase boundary and the grain pattern observed in the microstructure. Gradual transition from diffuse relaxor ferroelectric system to normal ferroelectric system was also studied. Enhanced ferroelectric response of the composition x=0.35 (Psat=32.03 μC/cm2, Pr=25.11 μC/cm2, EC=6.04 kV/cm, Rsq=1.28, Absolute area=3768, range of electric field=−37 to +37 kV/cm and recoverable energy density= 59.86 mJ/cm3), the improved dielectric behavior of the composition x=0.325 (er(max)=15,703, Tanδmax=0.02 and γ=1.79 (at 1 kHz)) and the high piezoelectric coefficient d33 (390 pC/N and 365 pC/N for x=0.325 and x=0.35 respectively), obtained in the study have confirmed the device worthiness of the synthesized ceramic compositions. This study was carried out to establish that, modulated high temperature synthesis will not deteriorate the electrical properties of the lead based system like PMN-PT, rather will assist the completion of perovskite phase formation, and thus enhance the functional response of the ceramic.