Earth abundant Cu2SnS3 (CTS) films were fabricated on glass substrates using facile dip coating technique. For exploring the role of annealing temperature in the formation of CTS films, the deposited films were annealed in an inert atmosphere at various temperatures. XRD analysis confirmed the formation of Cu2SnS3 and its monoclinic structure was further identified by Raman spectroscopy. Hall measurements revealed the p-type nature of films and observed a carrier concentration of similar to 10(17) cm(-3) for all the samples. High absorption coefficient value (alpha > 10(4) cm(-1)) and direct band gap in the range of 1.43 eV - 1.75 eV make the samples a suitable candidate in the field of photovoltaics. The influence of these process parameters on a solar cell based on CTS was analyzed by the SCAPS simulation program. At an annealing temperature of 475 degrees C, the simulated solar cell demonstrated the best power conversion efficiency PCE of 19.77 %.

In the present study, Cupric oxide thin films with varying thicknesses were successfully fabricated on a glass substrate at room temperature via dip coating technique. Highly crystalline CuO films with monoclinic symmetry were examined from XRD which was further confirmed with the help of Raman spectra. FESEM results showed a uniform coating surface with nano-sized grains without any agglomerations. The elemental composition of Cu and O atoms is in a 1:1 stoichiometric ratio for samples having higher thickness values. Strong absorption in the visible and nearby IR region makes the sample a viable choice in the field of photovoltaics. The estimated band gap values from the Tauc plot ranges from 1.10 eV to 1.26 eV. All the samples exhibited a p-type nature and their uniformity of resistance over the film surface was examined by resistance mapping. Hall measurements indicated the direct proportionality of sample resistivity with thickness.

Herein we report, tin (Sn) doped copper sulphide(CTS) thin films deposited on commercial glass substrates at room temperature throughin-situ chemical bath deposition. For the synthesis of CuS (CS) thin film aqueous solution of cupric chloride with thiourea was prepared. Triethanolamine was used as complexing agent. PH of the precursor solution has been adjusted using ammonium hydroxide solution. Doping was accomplished by Sn in to the chemical bath using hydrated stannic chloride solution. The structural, morphological properties of the thin films are investigated in detail. The XRD analysis revealed that both the doped and undoped films are polycrystalline in nature and was indexed to be of covellite CuS phase. Morphological characteristics showedrod shaped nanoparticles of size in range 150 nm- 250 nm for CuS film and spherical nanoparticles for the Sn doped CuS thin films whose size ranges in the same order as that of the CuS thin films. AFM revealed the rough surface topographyof the CuS film. UV-vis spectroscopy shows that optical energy band gap ofCuS thin film increases with Sn incorporation. The electrical conductivity of the pure CuS thin film is enhanced with Sn doping. The carrier concentrations determined from the Hall measurements came out to be 1017 cm−3, stating both the undoped and Sn doped CuS thin films were semiconducting in nature.

The quest for single-stage deposition of CuInGaSe2 (CIGS) is an open race to replace very effective but capital intensive thin film solar cell manufacturing processes like multiple-stage coevaporation or sputtering combined with high pressure selenisation treatments. In this paper the most recent achievements of Low Temperature Pulsed Electron Deposition (LTPED), a novel single stage deposition process by which CIGS can be deposited at 250 °C, are presented and discussed. We show that selenium loss during the film deposition is not a problem with LTPED as good crystalline films are formed very close to the melting temperature of selenium. The mechanism of formation of good ohmic contacts between CIGS and Mo in the absence of any MoSe2 transition layers is also illustrated, followed by a brief summary of the measured characteristics of test solar cells grown by LTPED. The 17% efficiency target achieved by lab-scale CIGS devices without bandgap modulation, antireflection coating or K-doping is considered to be a crucial milestone along the path to the industrial scale-up of LTPED. The paper ends with a brief review of the open scientific and technological issues related to the scale-up and the possible future applications of the new technology.

Nanocrystalline oxygen-deficient ZnO thinfilm sensors were prepared by spray pyrolysis technique using zinc acetate dissolved in propanol and water as precursor. Response of the sensor to target gases NO2 and H2S is studied. At optimum temperature of 200∘C, the sensors have a response of 3.32 to 7 ppm NO2 and 1.4 to 18 ppm of H2S gas. The analytical characterizations of the prepared sensors were performed using X-ray diffraction measurement, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Raman spectroscopy. Dynamic response of sensors to different concentrations of NO2 and H2S gas was tested at optimum temperature. Experimental data revealed the sensors to be more selective to NO2 gas with satisfactory response and recovery time.

This work projects photoluminescence (PL) as an alternative technique to estimate the order of resistivity of zinc oxide (ZnO) thin films. ZnO thin films, deposited using chemical spray pyrolysis (CSP) by varying the deposition parameters like solvent, spray rate, pH of precursor, and so forth, have been used for this study. Variation in the deposition conditions has tremendous impact on the luminescence properties as well as resistivity. Two emissions could be recorded for all samples—the near band edge emission (NBE) at 380 nm and the deep level emission (DLE) at ~500 nm which are competing in nature. It is observed that the ratio of intensities of DLE to NBE (/) can be reduced by controlling oxygen incorporation in the sample. - measurements indicate that restricting oxygen incorporation reduces resistivity considerably. Variation of / and resistivity for samples prepared under different deposition conditions is similar in nature. / was always less than resistivity by an order for all samples. Thus from PL measurements alone, the order of resistivity of the samples can be estimated.

NO2 gas Sensing characteristics of thin films of Zinc oxide obtained by spray pyrolysis were studied. The film thickness was about 550nm. The effect of indium doping on the sensor performance were also studied. The sensing behavior in the temperature range of 100–225°C was measured to find out the optimal working temperature.

In this paper we present studies on ZnO thin films (prepared using Chemical Spray pyrolysis (CSP) technique) doped in two different ways; in one set, 'single doping' using indium was done while in the second set, 'co-doping' using indium and fluorine was adopted. In the former case, effect of in-situ as well as ex-situ doping using In was analyzed. Structural (XRD studies), electrical (I-V measurements) and optical characterizations (through absorption, transmission and photoluminescence studies) of the films were done. XRD analysis showed that, for spray-deposited ZnO films, ex-situ doping using Indium resulted in preferred (0 0 2) plane orientation, while in-situ doping caused preferred orientation along (1 0 0), (0 0 2), (1 0 1) planes; however for higher percentage of in-situ doping, orientation of grains changed from (0 0 2) plane to (1 0 1) plane. The co-doped films had (0 0 2) and (1 0 1) planes. Lowest resistivity (2 x 10(-3) Omega cm) was achieved for the films, doped with 1% Indium through in-situ method. Photoluminescence (PL) emissions of ex-situ doped and co-doped samples had two peaks; one was the 'near band edge' emission (NBE) and the other was the 'blue-green' emission. But interestingly the PL emission of in-situ doped samples exhibited only the 'near band edge' emission. Optical band gap of the films increased with doping percentage, in all cases of doping. (C) 2011 Elsevier B. V. All rights reserved.

The polycrystalline ZnO thin film was deposited on the soda-lime glass substrate using chemical spray pyrolysis technique. Different types of precursor solutions were used for the film preparation. We studied the variations in structural, electrical and optical properties of the samples due to the change in concentration of propanol and ethanol in the precursor solutions. All the films had (002) plane orientation. Texture co-efficient, grain size and lattice parameters have been calculated. Grain size, optical transmission and electrical conductivity of the films enhanced with the increase in both the types of alcohol concentration. The films exhibited luminescence in two regions – ‘near band edge emission’ (NBE) (∼380nm) and ‘blue-green emission’ (∼503nm). Intensity of the blue-green emission varied with percentage as well as type of alcohol used in the precursor solution and from this study we could confirm that the oxygen antisite levels were reduced very much in samples prepared using solution containing higher percentage of alcohol, leading to the reduction of electrical resistivity. The lowest resistivity of 2×10−2Ωcm was obtained for the samples prepared using spray solution having water and propanol in 1:1 volume ratio.

Conductivity enhancement in spray pyrolysed ZnO thin film was achieved through post-deposition cooling. We present a comparison between the effect of cooling after the deposition of thin films by two different processes namely “regular cooling” and “inversion cooling”. X-ray photoelectron spectroscopy studies proved that zinc to oxygen ratio enhanced after the “inversion” process. It was observed that the process of “inversion” has caused dramatic improvement in the conductivity of ZnO thin film. The resistivity of the film decreased to 5×10−2 Ω cm with the inversion process. The films exhibited luminescence in two regions:“near band edge emission” (NBE; ∼380 nm) and “blue–green emission” (∼503 nm). The relationship between blue–green emission and oxygen concentration in the sprayed ZnO thin film was discussed.

Effect of varying spray rate on the structure and optoelectronic properties of spray pyrolysed ZnO film is analysed. ZnO films were characterised using different techniques such as X-ray diffraction (XRD), photoluminescence, electrical resistivity measurement, and optical absorption. The XRD analysis proved that, with the increase in spray rate, orientation of the grains changed from (101) plane to (002) plane. The films exhibited luminescence in two regions—one was the ‘near band-edge’ (NBE) (∼380nm) emission and the other one was the ‘blue-green emission’ (∼503nm). Intensity of the blue-green emission decreased after orientation of grains shifted to (002) plane. Scanning electron microscope (SEM) analysis of the films asserts that spray rate has major role in improving the crystallographic properties of the films. Moreover resistivity of the films could be lowered to 2.4×10−2Ωcm without any doping or post-deposition annealing.