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By using the chemical bath deposition approach, binary bismuth sulphides (Bi2S3) and chromium-doped ternary bismuth sulphides (Bi2−xCrxS3) thin films were effectively produced, and their potential for photovoltaic applications was examined. Structural elucidation revealed that Bi2S3 deposited by this simple and cost-effective method retained its orthorhombic crystal lattice by doping up to 3 at.%. The morphological analysis confirmed the crack-free deposition, hence making them suitable for solar cell applications. Optical analysis showed that deposited thin films have a bandgap in the range of 1.30 to 1.17 eV, values of refractive index (n) from 2.9 to 1.3, and an extinction coefficient (k) from 1.03 to 0.3. From the Hall measurements, it followed that the dominant carriers in all doped and undoped samples are electrons, and the carrier density in doped samples is almost two orders of magnitude larger than in Bi2S3. Hence, this suggests that doping is an effective tool to improve the optoelectronic behavior of Bi2S3 thin films by engineering the compositional, structural, and morphological properties. [ABSTRACT FROM AUTHOR]

CuO thin films deposited using SILAR coating technique with various dip-cycles. The prepared thin films were characterized to elucidate the structural and morphological features using analytical techniques such as XRD and SEM, respectively. It was found that along with the thickness of CuO films, the crystallinity and morphology of the deposited films have changed appreciably. The optical, electrical, and photosensing properties were also studied for deposited films. The optical and electrical properties for the thin film prepared with 100 dip-cycles were found best as compared to 50, 75, 125 dip-cycles, this may be due to improved crystallinity and uniform distribution of nanoclusters over the substrate. From the UV absorption studies, it was found that the CuO-100 thin-film has the highest absorption and a low bandgap of 1.67 eV. Also, the CuO with 100 dip sample exhibits a minimum resistivity of 2.98 × 102 Ω cm that leads to a higher carrier concentration of 4.63 × 1013 cm−3 and mobility of 4.53 cm2V−1 s−1. The I–V characteristics of all the deposited CuO samples were investigated and the CuO-100 dip cycle thin film is found to have a lower ideality factor of 5.4. Additionally, the Cu-100 thin film reveals a high responsivity and external quantum efficiency values of 1.67 × 10−1 A/W and 54%, respectively. Thus, in the SILAR dip-coating technique, the dipping cycles influence the CuO formation as well as their properties. [ABSTRACT FROM AUTHOR]

Ge25Se75 binary glass is prepared using melt-quenching technique. Thin films of 250 nm Ge25Se75 are thus evaporated using thermal evaporation method on a cleaned glass substrate. Energy dispersive X-ray analysis confirmed the starting percentage of the element. The effect of microwave irradiation on Ge25Se75 thin film with different illumination times (0–90 min) is studied. As confirmed by X-ray diffraction and scanning electron microscopy measurements, the nature of the as-prepared Ge25Se75 thin films appears to be amorphous. The type of optical transition has been demonstrated to be allowed indirect transitions. Moreover, the rest of the optical parameters have changed as a result of the microwave irradiation. It can be observed that, for Ge25Se75 thin films, the optical band gap increases as the illumination time increases. In terms of bond adjustments and changes in these films’ microstructure, this post-light increment in the band gap was decoded. Furthermore, while increasing the illumination time of microwave irradiation, the dispersion parameters of Ge25Se75 films were diminished. [ABSTRACT FROM AUTHOR]

Simple nebulizer spray technique used pristine and rare earth praseodymium (Pr) doped PbS thin films coated on soda-lime glass and their optoelectronic properties are reported. Dopant concentration-dependent structural, morphological, optical, and electrical properties of the prepared films were analyzed using X-ray diffraction, Raman spectrum, scanning electron microscopy, EDAX, UV–visible spectrum. X-ray diffraction study revealed the growth of polycrystalline face-centered cubic PbS thin films without any impurities. Increase of doping concentration resulted in a decrease in peak intensity indicating the degradation of crystalline quality. The Raman peaks observed at 190, 240 and 464 nm justified the formation of PbS phase. Surface morphology of the films showed dopant concentration dependent compact and uniform distribution of grains on substrate. EDAX studies legitimized the existence of Pb, S, and Pr in the prepared films. Energy band gap values of the films were gradually increased from 2.18 to 2.69 eV for the increase of doping concentration from 0 to 5 wt%. The prepared films exhibited increased currents for the increase of doping concentration with reasonable photosensing effect in I–V measurements. [ABSTRACT FROM AUTHOR]