Formation of High-Photoresponsivity BaSi Films by Radio-Frequency Sputtering and Evaluation of a BaSi/TiN/Glass Heterojunction by Transmission Electron Microscopy.

Barium disilicide (BaSi) is a thin-film solar cell material composed of abundant elements, and its application potential is further enhanced by its formation on inexpensive substrates, such as glass. The effect of the substrate temperature on the co-sputtering of BaSi and Ba targets to form BaSi films on Si(111) and TiN/glass substrates was investigated. Contrary to expectations, the photoresponsivity reached maximum values exceeding 5 and 2 A W, respectively, the highest value ever reported for as-deposited samples formed at 750 °C, more than 100 °C higher than those reported previously.

Polarity Control of an All-Sputtered Epitaxial GaN/AlN/Al Film on a Si(111) Substrate by Intermediate Oxidization.

The ability to control the polarity of an all-sputtered epitaxial GaN/AlN/Al film on a Si(111) substrate via intermediate oxidization was investigated. A stable surface of GaN on a Si substrate is a N-terminated surface (-c surface); hence, for electric device applications, the Ga-terminated surface (+c surface) is preferable. The GaN/AlN/Al film on Si(111) showed a -c surface, as confirmed by time-of-flight low-energy atom scattering spectroscopy (TOFLAS) and X-ray photoelectron spectroscopy (XPS).