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This paper describes the preparation and characterization of nanocrystalline CdxPb1−xS thin films by chemical bath deposition method with different Pb and Cd solute ratios. XRD, HRTEM and SAED patterns show the nanocrystalline nature of films with the co-existence of cubic, hexagonal and tetragonal phases, while micro-Raman spectra reveals the presence of cubic and hexagonal phases in the films. The average crystallite size of CdxPb1−xS estimated from TEM and XRD methods were nearly same. The chemical bonding present in the films was studied by FTIR spectral analysis. SEM images show uniformly distributed grains of different sizes over the substrates. Optical studies show the prominent blue shift in band gap energy (Eg) with the increase in Cd content in PbS. The increment of Cd addition to CdxPb1−xS has led to enhance the transmittance as well as band gap energy.

In this paper, the influence of thickness and post deposition annealing temperature on thermally evaporated molybdenum oxide films has been studied. The X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) are used for crystal structural and surface morphological characterization of the films, respectively. The XRD analysis showed that the presence of α-MoO3 and MoO2 crystalline phase of the films annealed at elevated temperature ~ 250 °C after deposition. The optical constants are determined from UV–Vis transmission spectra. The optical band gap and Urbach energy is found to be temperature dependent. The refractive index of the films is estimated by the optical method as well as cross-sectional SEM image analysis. It is found that the refractive index of the films increases from ~ 1.70 to 2.03 with the decrease in film thickness from ~ 2.9 to 1.7 µm. It is also observed that the refractive index decreased from ~ 2.03 to 1.61 with the increase in post deposition annealing temperature from room temperature (RT) to ~ 250 °C. Moreover, extinction coefficient, optical conductivity, porosity, and film density are investigated as a function of source-substrate distance and post deposition annealing temperature. The Photoluminescence (PL) properties of the films are also investigated by recording spectra under the excitation wavelength at 250 nm.

In this paper, a modified top-down method is adopted to synthesize highly stable and water-soluble Molybdenum trioxide quantum dots (MoO3 QDs) without any surfactants. In this sonication induced modified method, commercial Molybdenum Oxide powder and Hydrochloric acid were used as the precursor and etchant, respectively. The impact of sonication bath temperature on the morphological, microstructural, size, crystal-structural, and optical properties of MoO3 QDs have been systematically investigated. The controlled sonication bath temperature during the synthesis process results in the tunability of the QDs. The mechanism behind the controlled size of the QDs deeply rooted in the acoustic cavitation phenomenon. The synthesized QDs exhibit poly-crystallinity with mixed phases: orthorhombic (α-MoO3) and hexagonal (h-MoO3). Interestingly, the complete elimination of the hexagonal phase from the QDs has been observed as a function of sonication bath temperature.