Fabrication and characterization of BaSi₂ epitaxial films over 1 µm in thickness on Si(111)

Abstract

We attempted to fabricate a -axis-oriented BaSi 2 epitaxial films up to 2180 nm in thickness. First, we investigated the influence of growth temperature and growth rate on the crystalline quality of approximately 400-nm-thick BaSi 2 layers, and then optimized the above two growth conditions based on X-ray diffraction measurements. We next grew BaSi 2 films with various layer thicknesses at 580 °C in the range between 100 and 2180 nm, and characterized their properties. The a -axis-oriented BaSi 2 thick epitaxial films had three epitaxial variants rotating 120° with each other around the surface normal. The microwave photoconductive decay measurements for the 1640-nm-thick BaSi 2 epitaxial film showed that the minority-carrier lifetime was approximately 8 µs at room temperature. These achievements open up the possibilities of thin-film solar cell applications of BaSi 2 .