An In-Depth Analysis of CdTe Thin-Film Deposition on Ultra-Thin Glass Substrates via Close-Spaced Sublimation (CSS)

This study evaluated the impact of the deposition pressure on the formation of cadmium telluride (CdTe) thin films on ultra-thin (100 mu m) Schott glass substrate at high temperature (T > 450 degrees C) by Close-Spaced Sublimation (CSS) technique. CdTe thin films were grown under the pressure range of 1 Torr to 200 Torr to explore the impact of deposition pressure on CdTe thin-film properties. The microstructural, compositional and optoelectrical characteristics were examined. X-ray Diffraction (XRD) analysis revealed the cubic phase crystallite CdTe films with (111) preferential orientation. Scanning Electron Microscopy (SEM) demonstrated that the CdTe morphology and grain size could be regulated via the deposition pressure, whereby maximum grain growth was detected at low pressure (1-5 Torr). The thickness of CdTe films was reduced from 6 mu m to 1.5 mu m with the rise in deposition pressure. Moreover, the optical direct energy gap was derived in the range of 1.65-1.69 eV for the pressure value of 200 Torr to 1 Torr. Carrier density and resistivity were found to be in the order of 10(13) cm(-3) and 10(4) omega cm, respectively. The experimental results suggest that the pressure range of 1-5 Torr may be ideal for CSS-grown CdTe films on flexible ultra-thin glass (UTG) substrates.

Automated summary

This study evaluated the impact of deposition pressure on the formation of CdTe thin films grown on ultra-thin glass substrates at high temperature using the CSS technique. The results showed that low pressure (1-5 Torr) led to maximum grain growth in CdTe films, while the film thickness and optical properties varied with different deposition pressures.