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1.
Davoud Dastan Seyedeh Leila Panahi Nandu B. Chaure 《Journal of Materials Science: Materials in Electronics》2016,27(12):12291-12296
A dip-coating technique was employed to prepare anatase phase of titania thin films. Fluorine doped tin oxide substrates were used to prepare titania thin films. The samples were annealed at 550 °C for 18 h. X-ray diffraction results revealed the amorphous and anatase phases of TiO2 for as-synthesized and annealed samples, respectively. The crystallite size of anatase TiO2 thin films was almost 25 nm for annealed samples. UV–visible confirmed the energy band gap 3.86 and 3.64 eV for as-prepared and calcinated titania thin films. The reduction in the energy band gap could be due to the change in crystallization and agglomeration of small grains after calcination. The morphology of the prepared films was investigated by field emission scanning electron microscopy which demonstrated the agglomeration of spherical particles of TiO2 with average particle size of about 30 nm. The molecular properties (chemical bonding) of the samples were investigated by means of Fourier Transform Infrared (FTIR) spectroscopy. FTIR analysis exhibited the formation of titania, functional group OH, hydroxyl stretching vibrations of the C–OH groups, bending vibration mode of H–O–H, alkyl C–H stretch, stretching band of Ti–OH, CN asymmetric band stretching, and C=O saturated aldehyde. 相似文献
2.
I.M. Dharmadasa N.B. Chaure A.P. Samantilleke A. Hassan 《Solar Energy Materials & Solar Cells》2008,92(8):923-928
Metal contacts to chemically etched Cu(InGa)(SeS)2 layers have been investigated using current–voltage and capacitance–voltage techniques. Oxidising chemicals enhance the Fermi level pinning at metal/Cu(InGa)(SeS)2 interfaces. The formation of a Schottky barrier at metal/p-Cu(InGa)(SeS)2 interface is dominated by Fermi level pinning at one of the four levels, 0.77±0.02, 0.84±0.02, 0.93±0.02 and 1.03±0.02 eV above the valence band maximum. These observed levels determined from current–voltage measurements show a good agreement with some of the previously published photoluminescence, deep level transient spectroscopy and photo acoustic spectroscopy observations. The capacitance–voltage measurements showed that this material has near ideal doping concentration of 1.0×1016 cm−3 for fabricating solar cell devices. 相似文献
3.
X-ray diffraction, atomic force microscopy and electrical studies were performed on 2-3 μm thick diamond films on silicon substrates. The films were produced by the microwave plasma chemical vapour deposition method. The films were polycrystalline having a grain size of 32.1 nm. From room temperature current-voltage measurements, it was found that the charge transport mechanism was due to the thermionic emission over the potential barrier of 1.3 eV. 相似文献
4.
This paper presents a systematic study of electric field assisted growth of self-organized cadmium sulphide (CdS) quantum dots (Q-CdS). CdS thin films of self-organized quantum dot like structure with different particle size have been successfully deposited simply by varying the concentration of surfactant in the reaction matrix. The model to describe the self-organization is also discussed. The size of CdS nanoparticles can be altered from 68 nm (corresponding to bulk) to 2 nm. The structural, optical, and morphological properties of Q-CdS films have been investigated. A blue shift has been observed in optical absorption and photoluminescence spectra. The strained growth of Q-CdS films has been observed. The microstructural strain calculated from peak broadening reveals an increase in strain with decreasing particle size. This study may provide a convenient method to deposit size selective and organized nanocrystalline semiconductor thin films. 相似文献
5.
A.B. Panda K. Harish S.V. Chaure V.S. Jadhav D. Sasmal A.K. Das I. Banerjee 《Surface & coatings technology》2010,205(5):1611-1617
TiO2 thin films have been deposited at different Ar:O2 gas ratios (20:80,70:30,50:50,and 40:60 in sccm) by rf reactive magnetron sputtering at a constant power of 200 W. The formation of TiO2 was confirmed by X-ray photoelectron spectroscopy (XPS). The oxygen percentage in the films was found to increase with an increase in oxygen partial pressure during deposition. The oxygen content in the film was estimated from XPS measurement. Band gap of the films was calculated from the UV-Visible transmittance spectra. Increase in oxygen content in the films showed substantial increase in optical band gap from 2.8 eV to 3.78 eV. The Ar:O2 gas ratio was found to affect the particle size of the films determined by a transmission electron microscope (TEM). The particle size was found to be varying between 10 and 25 nm. The bactericidal efficiency of the deposited films was investigated using Escherichia coli (E. coli) cells under 1 h UV irradiation. The growth of E. coli cells was estimated through the Optical Density measurement by UV-Visible absorbance spectra. The qualitative analysis of the bactericidal efficiency of the deposited films after UV irradiation was observed through SEM. A correlation between the optical band gap, particle size and bactericidal efficiency of the TiO2 films at different argon:oxygen gas ratio has been studied. 相似文献
6.
A.B.M.O. Islam N.B. Chaure J. Wellings G. Tolan I.M. Dharmadasa 《Materials Characterization》2009,60(2):160-163
Zinc telluride (ZnTe) thin films have been deposited on glass/conducting glass substrates using a low-cost electrodeposition method. The resulting films have been characterized using various techniques in order to optimize growth parameters. X-ray diffraction (XRD) has been used to identify the phases present in the films. Photoelectrochemical (PEC) cell and optical absorption measurements have been performed to determine the electrical conductivity type, and the bandgap of the layers, respectively. It has been confirmed by XRD measurement that the deposited layers mainly consist of ZnTe phases. The PEC measurements indicate that the ZnTe layers are p-type in electrical conduction and optical absorption measurements show that their bandgap is in the range 2.10–2.20 eV. p-Type ZnTe window materials have been used in CdTe based solar cell structures, following new designs of graded bandgap multi-layer solar cells. The structures of FTO/ZnTe/CdTe/metal and FTO/ZnTe/CdTe/CdHgTe/metal have been investigated. The results are presented in this paper using observed experimental data. 相似文献
7.
Ashwini B. Rohom Priyanka U. Londhe Ganesh R. Bhand Manorama G. Lakhe Nandu B. Chaure 《Journal of Materials Science: Materials in Electronics》2016,27(12):12374-12384
CIS thin films have been grown electrochemically from an aqueous electrolyte at room temperature on fluorine doped tin oxide coated glass substrate at different deposition potentials ranging from ?0.7 to ?1.0 V versus Ag/AgCl reference electrode. Cyclic voltammetry was studied at slow scan rate to optimize the deposition potential. The thin film samples were selenized in a tubular furnace at 400 °C for 20 min. X-ray diffraction and Raman analysis was used to study the structural properties. Optical absorption, scanning electron microscopy and energy dispersive X-ray analysis (EDAX) have been used to investigate the band-gap, surface morphology and compositional analysis. Electrical properties were studied with the help of current–voltage measurements. Conductivity type for CIS thin films was studied by using photo-electrochemical study. The prominent reflections (112), (204/220) and (312/116) of tetragonal chalcopyrite CIS have been revealed for all as-grown and selenized samples. The energy band gap of the selenized CIS thin film deposited at various deposition potentials was found to be ~1.03 to 1.24 eV. Granular, uniform and void free surface was observed in as-prepared sample, while large clusters were noticed in selenized samples. EDAX results reveal that the stoichiometric CIS thin film are deposited ?0.8 V, however, Cu-rich and In-rich CIS layers were grown at lower and higher cathodic deposition potentials, deviated from ?0.8 V. The values ideality factor (η) calculated from I–V measurements were found to be decreased upon selenization. The Raman spectra of stoichiometric CIS thin film shows dominant A1 mode with spectral features sensitive to the microcrystalline quality of the layers. A ordered defect compound layer and secondary phases of CuSe are observed in In-rich and Cu-rich CIS layers, respectively. 相似文献
8.
Priyanka U. Londhe Ashwini B. Rohom Ganesh R. Bhand Sujata Jadhav Manorama G. Lakhe Nandu B. Chaure 《Journal of Materials Science: Materials in Electronics》2017,28(7):5207-5214
Zinc sulfide (ZnS) thin films have been deposited onto fluorine doped tin oxide and microscopic glass substrates from an aqueous alkaline reaction by chemical bath deposition. The effect of concentrations of hydrazine hydrate (HyH) (complexing agent) on the deposit is studied. X-ray analysis confirm the growth of nanocrystalline ZnS thin films with reflections (111), (220) and (311) correspond to cubic crystalline phase. TEM results support the growth of cubic ZnS layers. The energy band gap was successfully tailored from 2.77 to 3.80 eV. Photoluminescence study indicates a strong band-edge emission with some defect like vacancies. It was also noticed that HyH plays an important role on the nucleation. The remarkable improvement in the growth rate of ZnS thin films have been observed upon increasing the contents of HyH. Nearly stoichiometric ZnS layer was obtained upon annealing prepared with 2.5 M HyH. The crystallinity was found to be increased upon annealing the layers. The ideality factor for the ZnS layers prepared with 0 and 1.0 M HyH were obtained?~1.71 and 1.24, respectively. The capacitance–voltage plots behave according to Schottky–Mott theory. The doping concentrations?~1017 and 1018 cm?3 were calculated for the layers deposited with 0 and 1.0 M HyH, respectively. 相似文献
9.
Size quantised cadmium sulphide (CdS) nanocrystalline thin films with different particle sizes and stoichiometric ratios were successfully grown on indium tin oxide substrates using an aqueous synthetic route. The effect of cadmium (Cd) to sulphur (S) ratio on the optical properties of CdS nanocrystalline films was investigated using EDAX, UV-vis spectroscopy, photoluminescence and Raman spectroscopy. A satisfactory stoichiometric condition was achieved for 0.13 M concentration of thiourea whereas concentrations in the range of 1-1.2% of mercaptoethanol capping agents produced values much smaller than Wannier exciton diameter for CdS grain sizes, leading to quantum confinement. Photoluminescence emission bands and Raman peaks were analysed for the physical understanding of optimum growth of CdS quantum dots. 相似文献
10.
Nandu B Chaure Andrew N Cammidge Isabelle Chambrier Michael J Cook Markys G Cain Craig E Murphy Chandana Pal Asim K Ray 《Science and Technology of Advanced Materials》2011,12(2)
Solution-processed films of 1,4,8,11,15,18,22,25-octakis(hexyl) copper phthalocyanine (CuPc6) were utilized as an active semiconducting layer in the fabrication of organic field-effect transistors (OFETs) in the bottom-gate configurations using chemical vapour deposited silicon dioxide (SiO2) as gate dielectrics. The surface treatment of the gate dielectric with a self-assembled monolayer of octadecyltrichlorosilane (OTS) resulted in values of 4×10−2 cm2 V−1 s−1 and 106 for saturation mobility and on/off current ratio, respectively. This improvement was accompanied by a shift in the threshold voltage from 3 V for untreated devices to -2 V for OTS treated devices. The trap density at the interface between the gate dielectric and semiconductor decreased by about one order of magnitude after the surface treatment. The transistors with the OTS treated gate dielectrics were more stable over a 30-day period in air than untreated ones. 相似文献