Pawan Kumar; Amit Sanger; Arvind Kumar; Davinder Kaur; Ramesh Chandra
Abstract
In the present work, gas sensing properties of Copper (Cu) doped Zinc Oxide (ZnO) thin films have been investigated. The nanostructured ZnO and Cu doped ZnO (CZO) thin films have been synthesized using DC magnetron sputtering on glass substrates. The effect of hydrophobicity and surface roughness of ...
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In the present work, gas sensing properties of Copper (Cu) doped Zinc Oxide (ZnO) thin films have been investigated. The nanostructured ZnO and Cu doped ZnO (CZO) thin films have been synthesized using DC magnetron sputtering on glass substrates. The effect of hydrophobicity and surface roughness of the CZO thin films on the carbon monoxide (CO) gas sensing performance have been examined. Fast response time (47 sec) and an optimum recovery time (~ 86 sec) have been witnessed at an adequate temperature of 250°C for the samples having contact angle ~ 131o and surface roughness ~ 14.86 nm. Hydrophobicity of the surface provides short recovery time by opposing the existence of water-vapour on the surface. Copyright © 2018 VBRI Press.
Narendra Singh; Davinder Kaur
Abstract
Ultrathin silicon carbide (SiC) films were grown on p type Si (100) substrate by RF magnetron sputtering at constant substrate temperature of 7000C for investigating thickness dependence of structural and photoluminescence properties. The structural and Photoluminescence properties were measured by X-ray ...
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Ultrathin silicon carbide (SiC) films were grown on p type Si (100) substrate by RF magnetron sputtering at constant substrate temperature of 7000C for investigating thickness dependence of structural and photoluminescence properties. The structural and Photoluminescence properties were measured by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and photospectrometer respectively. X-ray diffraction pattern revealed (102) and dominant (105) reflections which corresponds to 4H-SiC and an enhancement in (105) peak intensity with increasing thickness was also observed. The thickness measured by X-ray reflectometry (XRR) reduces from ~ 46 nm to 12 nm by decreasing deposition time (40-10 minute) which in turn reduces the crystallite size. Photoluminescence spectra show a broad peak extending from ultraviolet to blue region centered at ~ 385 nm for film of thickness ~ 46 nm (deposition time 40 min). A shifting in Photoluminescence peak towards shorter wavelength (blue shift) with decreasing SiC ultrathin film thickness was observed, which could be attributed to quantum confinement effect. The improved Photoluminescence in ultrathin nanocrystalline SiC films could make it a potential candidate in optoelectronic and biomedical applications. Copyright © 2017 VBRI Press.
Sharmistha Anwar; Shahid Anwar
Abstract
Present work is focused on various properties of thermally annealed tungsten nitride (WN) film. Tungsten nitride thin films on silicon (100) substrates were deposited via reactive magnetron sputtering technique. Initially Ar/N2 flow ratio was optimized by varying N2 gas flow between 5 to 25 sccm. 20:5 ...
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Present work is focused on various properties of thermally annealed tungsten nitride (WN) film. Tungsten nitride thin films on silicon (100) substrates were deposited via reactive magnetron sputtering technique. Initially Ar/N2 flow ratio was optimized by varying N2 gas flow between 5 to 25 sccm. 20:5 (Ar:N2) was found to be the best for W2N phase formation. Using optimized condition, a set of WN deposited and then annealed at different temperatures i.e. 200°C, 400°C and 600°C for two hours each. Various characterizations have been done using X-ray diffraction, four probe resistivity and nano-indentation test. XRD results suggest formation of pure W2N crystalline phase of the films with face centered cubic structure. The resistivity result shows the decrease of resistivity value with increase in annealing temperature. Nano-indentation results showed hardness and elastic modulus values at 5mn load does not vary much with annealing at different temperatures. Structural, mechanical and electrical studies showed that the samples were stable up to 600°C. Thus, tungsten nitride thin films will contribute as a material suitable for long time exposure at elevated temperature for application of cutting tools. Copyright © 2017 VBRI Press.
Suresh Addepalli; Lakshmi Ganapathi Kolla; Uthanna Suda
Abstract
Aluminium titanate (Al2TiO5) thin films were deposited at room temperature by DC reactive magnetron sputtering. To make appropriate films for potential gate dielectric applications, we investigated the influence of annealing temperature on the structural, chemical and dielectric properties of Al2TiO5 ...
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Aluminium titanate (Al2TiO5) thin films were deposited at room temperature by DC reactive magnetron sputtering. To make appropriate films for potential gate dielectric applications, we investigated the influence of annealing temperature on the structural, chemical and dielectric properties of Al2TiO5 thin films. From XPS studies, in as-deposited films, it has been observed that the presence of Al3+ and Ti4+oxidation states which correspond to Al2O3 and TiO2 respectively. After annealing at 400 °C in oxygen ambient, the binding energies of Al 2p, Ti 2p and O 1s were shifted by ~ 1 eV towards lower binding energy. This indicates the formation of an intermediate compound of Al2O3 and TiO2. The extracted Al, Ti and O ratio was 2:1:5 and it confirms the formation of Al2TiO5. XRD studies indicate that the as-deposited films were amorphous in nature. After annealing at 400 °C, diffraction peak at 2θ = 50.6° along (200) plane corresponds to aluminum titanate (Al2TiO5) has been observed. Metal-Insulator-Semiconductor (MIS) capacitors were fabricated and characterized to estimate the dielectric properties of the deposited films. The as-deposited films show low dielectric constant (κ = 8.1) and high leakage current density (J = 2.4x10-2 A/cm2 at -1V) values. After annealing at 400 °C the films show improved dielectric constant (κ = 9.4) and leakage current density (J = 4.6x10-9 A/cm2 at -1V) values. The enhancement in the device properties can be attributed to the improved oxide and interface quality after annealing. Equivalent oxide thickness (EOT) of less than 1nm is required to use Al2TiO5 as an alternate gate dielectric to SiO2 in CMOS industry. To achieve this scaling of the dielectric thickness (<5 nm) is needed, which is under investigation. Copyright © 2017 VBRI Press.
Sharmistha Anwar; Barada K. Mishra; Shahid Anwar
Abstract
Thermoelectric thin films of Bi2Te3 and Sb2Te3 were deposited by using sputtering technique. Structural characterizations of as deposited films were done by using X-ray diffraction (XRD), Energy Dispersive X-ray Analysis and electrical properties have been evaluated at room temperature by Seebeck coefficient ...
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Thermoelectric thin films of Bi2Te3 and Sb2Te3 were deposited by using sputtering technique. Structural characterizations of as deposited films were done by using X-ray diffraction (XRD), Energy Dispersive X-ray Analysis and electrical properties have been evaluated at room temperature by Seebeck coefficient and electrical resistivity measurement. These sputtered films were established to be polycrystalline and of desired single phase in nature with stoichiometric composition. The Seebeck coefficient and electrical resistivity of p-type Sb2Te3 thin film and n-type Bi2Te3 thin films were found to be about 111 μV/K, 8.25×10-5 Ω- m and −98.52μV/K, 5.87×10-6 Ω-m, respectively whereas to that of n-type Bi2Te3-Sb2Te3 multilayer having 5BL combination is −145μV/K, 9.31×10-5 Ω-m and 10BLcombination is −170 μV/K, 9.86×10-5 Ω-m. The power factor value has increased reasonably well in case of multilayer as compared to that of individual single layer, maximum power factor value 2.95×10-3 W/m K2 has been achieved for 10BL combination. These results indicate that good quality antimony telluride, bismuth telluride and their multilayer thin films can be grown easily by using sputtering technique. It also suggests that these types of nano-structuring (multilayer structure) in these categories of materials can be promissory engineering concept for the fabrication of micro-Peltier modules.
