Jaspal P. Bange

Growth and Characterization of Sio 2 Films Deposited by Flame Hydrolysis Deposition System for Photonic Device Application

There are various techniques for the deposition of SiO2 films on silicon. Flame Hydrolysis Deposition (FHD) techniques is the most economical technique for the deposition of SiO2 films. In this technique the SiO2 films are deposited by hydrolysis of SiCl4 in a high temperature H2-O2 flame. In the present study we present the growth of SiO2 films by indigenously developed FHD system and organic compound Tetraethoxyorthosiliate/Tetraethoxysilane TEOS as source of silicon. The films deposited by the FHD system are porous and need annealing at higher temperatures for the densification. We present here for the first time direct dense glassy transparent SiO2 films deposited by our FHD system. The optical properties of the deposited films were studied by ellipsometery. FTIR spectroscopy was carried out to study the various characteristic peaks of SiO2 bonds. The peaks corresponding to Si-O-Si stretching, bending and rocking modes are observed at 1090 cm −1 , 812 cm −1 and 463 cm −1 respectively. The absence of peaks corresponding to the OH bond in the deposited film reveals that the deposited films are most suitable for the photonic devices application. The surface analysis was carried out using SEM. The EDAX of the deposited film confirms the composition of the Si and O in the deposited film.

Blue luminescence from Ba0.05Zn0.95O nanostructure

Blue luminescence has been realized from ternary alloy compound of Ba0.05Zn0.95O nanostructure. Ba0.05Zn0.95O nanostructure was synthesized by sol–gel spin coating method on a glass substrate. The deposited samples were characterized by X-ray diffractometer (XRD), UV–visible spectrophotometer, field emission scanning electron microscopy (FESEM) and photoluminescence (PL). XRD pattern of Ba0.05Zn0.95O nanostructure film reveals polycrystalline nature with hexagonal wurtzite structure. FESEM-EDAX analysis shows that Ba was successfully incorporated into ZnO with uniform granular nanostructure having average grain size of 30xa0nm. Analysis of transmission, band gap and thickness have been carried out to investigate effect of post annealing temperature. All the deposited samples exhibit more than 95xa0% transparency in the visible region. It was observed that the average transmission of the deposited films gradually increase with increasing annealing temperature. Thickness of the synthesized samples were found to be decrease with an increase in post annealing temperature. Optical band gap energy was found to be increased from 3.182 to 3.28xa0eV with increasing annealing temperature. The dominant peak at 467xa0nm corresponding to the intense blue emission in the visible range was observed in the PL spectra.

Optical and structural properties of nanoscale undoped and cerium doped ZnO with granular morphology

Nanoscale undoped and cerium (Ce) doped zinc oxide (ZnO) thin films have been synthesized by sol gel spin coating technique on glass substrate with optimum post annealing temperature of 375xa0°C. We have investigated that incorporation of cerium in ZnO could alter the morphological, optical and photoluminescence properties of the deposited samples. The X-ray diffraction spectrum reveals that all the synthesized samples have hexagonal wurtzite structure and show strong peak preferentially oriented along the (002) c-axis direction of the substrate. The crystalline size of undoped and Ce doped ZnO thin films were deduced to be 30 and 15xa0nm respectively, which signifies that the crystalline size has been decreased with cerium doping. From the optical studies, the average transmittance of both the films exhibited more than 90xa0% transparency in visible region (400–700xa0nm). Moreover, the optical band gap of Ce doped ZnO thin films increases from 3.235 to 3.278xa0eV. Field emission scanning electron microscopy study reveals uniform granular structure of the prepared samples. Mighty peak observed at 398xa0nm got broadened and less intense due to cerium doping and other shoulder peaks almost vanished as investigated from photoluminescence spectra.

Growth and Characterization of SiO2 Films for the Fabrication of Optical Waveguides

The SiO2 films grown by Plasma Enhanced Chemical Vapor Deposition (PECVD) system are used for the fabrication of optical waveguides due to their several advantages such as low temperature deposition, controlled refractive index and low tensile stress. These films are preferably used as core and cladding layers in the waveguide. The waveguides formed by the films with controlled refractive index are found to be most suitable for the coupling with the optical fibers as the R.I. are in the range of 1.45 to 1.47. It has been found from the observations that the SiO2 film grown at 300° C shows the excellent properties i.e. better thickness, precisely controlled refractive index and comparatively low tensile stress. The present paper reports the study of the deposition of SiO2 films with indigenously developed PECVD system and their characterization.

Effect of cerium composition on optical and structural properties of cerium doped ZnO nanowires

Synthesis of cerium (Ce) doped zinc oxide (ZnO) nanowire has been carried out using chemical bath deposition over seed layer. The seed layer of Ce doped ZnO thin film was deposited by spin coating method. Effect of Ce doping on optical and structural properties of nanowire has been explored to optimize the performance of nanowires for their applicability in light emitting devices. High resolution field emission scanning electron microscopy (FESEM) clearly reveals nanowire growth for 15% of Ce in ZnO. Optical band gap of the films was found to increase with an increase in Ce concentration in ZnO. All Ce doped ZnO thin films exhibits more than 90% transparency in the visible region and show absorption sharply in ultra-violet region at approximate 375xa0nm. Transmittance of the nanowire in visible region is showing an average transmittance of 61%. The photoluminescence (PL) spectra in all samples exhibit a strong ultraviolet emission at the near band edge centered at 389xa0nm due to free exciton recombination. A broad blue visible emission peak for all the samples located at 467xa0nm was seen to be originated due to the interstitial position of Zn2+ ions.

Study of Varying Tubes in Carbon Nanotube FET Based Inverter

In today’s era, Carbon Nanotubes (CNT) are becoming more popular than CMOS due to its electrical and mechanical properties. The devices using Carbon Nanotube FET’s (CNTFET) provide fast switching, high electron mobility, high current density as well as high transconductance. In this paper a Stanford Leland junior universities standard mode of CNTFET is used for implementing HSPICE . This work involves study of varying number of nanotubes in CNTFET based inverter . Initially the optimization for gate oxide thickness with number of nanotubes has been done. The optimized result shows that maximum average output power of 2.0503 µW is observed with gate oxide thickness of 4 nm and 40 nanotubes. These optimized parameters were used to study effect on varying number of CNT on gain of CNT based inverter. The study reveals that increasing number of CNT’s does not affect on the gain.

Structural and Optical Properties of Single Crystalline Cerium Doped ZnO Thin Films

Ce doped ZnO thin films were prepared on a glass substrate by sol-gel spin coating technique. Effect of post annealing temperature from 250 to 450 °C on structural and optical properties of Ce doped ZnO thin films were studied. The influence of temperature on transparency, bandgap and crystallite size of Ce doped ZnO was observed. The nano thin films were characterized by X-ray Diffractometer and UV-Vis Spectrophotometer. Crystallinity of the deposited thin films was found to be improved with temperature. Increasing the post annealing temperature (250°–450 °C), increases the grain size of the samples gradually from 15.41 to 26.54 nm. In addition to the effect of post annealing temperature, the influence of average transmission, absorption, and band gap of the Ce doped ZnO thin films was investigated for optoelectronics applications.