Sumita Rani

Removal of methylene blue and rhodamine B from water by zirconium oxide/graphene

Abstract Methylene blue (MB) and rhodamine B dyes (RB) were degraded from water using zirconium oxide (ZrO2) and zirconium oxide/graphene composites (ZrO2/GR) as photocatalyst. The photocatalytic efficiency was calculated from absorption spectra obtained using UV–visible spectroscopy. It has been observed that photodegradation time as well as photocatalytic efficiency increase with the concentration of catalyst up to a certain limit after which effect was reversed. The degradation was studied as a function of pH also. It was found that photocatalytic efficiency was more in alkaline medium than acidic medium. Degradation of RB takes place at higher value of pH as compared to MB. The degradation time for MB was 1 h using ZrO2 which get reduced to 32 min using ZrO2/GR composite and for RB it reduced to 40 min (using ZrO2/GR) from 80 min (ZrO2).

Amide Functionalized Graphene Oxide Thin Films for Hydrogen Sulfide Gas Sensing Applications

Amide graphene oxide (AGO) has been achieved by functionalization of graphene oxide (GO) through chemical route using 2-aminothiazole. GO and AGO were characterized and compared using Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, energy dispersive X-ray, and Raman spectroscopy. Gas sensor devices were developed by depositing film of GO/AGO between aluminum electrodes on SiO2/Si substrate. The sensing performance of AGO and GO has been investigated in terms of change in conductivity. It has been found experimentally that AGO exhibits significantly better reversible sensing response to hydrogen sulphide (H2S) gas in comparison with GO.

Deposition and evaluation of self assembled monolayer as diffusion barrier for copper metallization for integrated circuits

Self Assembled Monolayer was deposited on silicon substrate using 3-aminopropyltrimethoxysilane (APTMS). The diffusion barrier properties of this layer against copper diffusion were studied. For this purpose, Cu/SiO2/Si and Cu/SAM/SiO2/Si structures were compared. The samples were annealed at various temperatures in vacuum ambient. The characterization was performed using X-Ray diffraction, Four Probe Resistivity measurement and Capacitance-Voltage technique. C-V measurement was performed by applying Bias Thermal Stress (BTS). XRD Results indicated that combination of SiO2/SAM worked as diffusion barrier layer up to 600 °C whereas SiO2 could work as barrier only up to 400 °C. C-V and resistivity plots also supported the possibility of using SAM as a good barrier for copper metallization in VLSI systems.Self Assembled Monolayer was deposited on silicon substrate using 3-aminopropyltrimethoxysilane (APTMS). The diffusion barrier properties of this layer against copper diffusion were studied. For this purpose, Cu/SiO2/Si and Cu/SAM/SiO2/Si structures were compared. The samples were annealed at various temperatures in vacuum ambient. The characterization was performed using X-Ray diffraction, Four Probe Resistivity measurement and Capacitance-Voltage technique. C-V measurement was performed by applying Bias Thermal Stress (BTS). XRD Results indicated that combination of SiO2/SAM worked as diffusion barrier layer up to 600 °C whereas SiO2 could work as barrier only up to 400 °C. C-V and resistivity plots also supported the possibility of using SAM as a good barrier for copper metallization in VLSI systems.

Synthesis and characterization of graphene thin film by thermal reduction

Graphene thin film has been synthesize by thermal reduction of graphene oxide (GO) formed by modified Hummer’s method. GO solution was prepared in DI water and subsequently deposited on the SiO2/Si substrate by spin casting at 2000rpm. The prepared samples were thermally reduced at different temperature in vacuum. The XRD results confirms the reduction of GO. Four probe conductivity measurement technique was used for the conductivity measurement.