Surface and microstructural properties of SnO2 thin films grown on p-InP (100) substrates at low temperature

SnO2 thin films were grown on p-InP (100) substrates by using radio-frequency magnetron sputtering at low temperature. Atomic force microscopy images showed that the root mean square of the average surface roughness of the SnO2 film was 22.6 إ, and X-ray diffraction and transmission electron microscopy (TEM) measurements showed that the SnO2 thin films grown on p-InP substrates were polycrystalline. Auger electron spectroscopy and bright-field TEM measurements showed that the SnO2 thin layers grown on p-InP substrates at 200°C had no significant interdiffusion problems. However, a thin interfacial layer of unknown origin was detected between the SnO2 film and the substrate. These results indicate that the SnO2 epitaxial films grown on p-InP (100) substrates at low temperature hold promise for potential devices based on InP substrates, such as superior stability varistors and high-efficiency solar cells. Even the structure with the unintentionally grown interfacial layer might be used for high-efficiency solar cells.