This paper reports that CaSb thin films have been co-deposited on soda-lime glass substrates. The GaSb thin film structural properties are characterized by Raman spectroscopy. The Sb-A1g/GaSb-TO ratio decreases rapidly with the increase of substrate temperature, which suggests a small amount of crystalline Sb in the GaSb thin film and suggests that Sb atoms in the thin film decrease. In Raman spectra, the transverse optical （TO） mode intensity is stronger than that of the longitudinal optical （LO） mode, which indicates that all the samples are disordered. The LO/TO intensity ratio increases with increasing substrate temperature which suggests the improved polycrystalline quality of the CaSb thin film. A downshift of the TO and LO frequencies of the polycrystalline CaSb thin film to single crystalline bulk GaSb Raman spectra is also observed. The uniaxial stress in GaSb thin film is calculated and the value is around 1.0 GPa. The uniaxial stress decreases with increasing substrate temperature. These results suggest that a higher substrate temperature is beneficial in relaxing the stress in GaSb thin film.
We report optical and electrical properties of polycrystalline GaSb thin films which were successfully grown by co-evaporation on soda-lime glass substrates. The thin films have preferential orientation of the （111） direction. SEM results indicate that the average grain size of GaSb thin film is 500 nm with the substrate temperature of 560 ℃. The average reflectance of GaSb thin film is about 30% and the absorption coefficient is of the order of 10^4 cm^-1. The optical bandgap of GaSb thin film is 0.726 eV. The hole concentration shows a clear increasing trend as the Ga-evaporation-temperature/Sb-evaporation-temperature （TGa/Tsb） ratio increases. When the Ga crucible temperature is 810 ℃ and the antinomy crucible temperature is 415 ℃, the hole concentration of polycrystalline GaSb is 2 × 10^17 cm^-3 and the hole mobility is 130 cm^2/（V·s）. These results suggest that polycrystalline GaSb thin film is a good candidate for the use as a cheap material in TPV cells.
The scaling behavior and optical properties of Zn（S, O and OH） thin films deposited on sod^-lime glass substrates by chemical bath deposition method were studied by combined roughness measurements, scanning electron microscopy and optical properties measurement. From the scaling behaviour, the value of growth scaling exponent β2 0.38±0.06, was determined. This value indicated that the Zn（S, O, OH） film growth in the heterogeneous process was influenced by the surface diffusion and shadowing effect. Results of the optical properties measurements disclosed that the transmittance of the film was in the region of 70%-88% and the optical properties of the film grown for 40 min were better than those grown under other conditions. The energy band gap of the film deposited with 40 min was around 3.63 eV.
