[19p-F202-1~16] 13.2 Exploratory Materials, Physical Properties, Devices

▲ [19p-F202-15] Growth of Type II Germanium Clathrate Na_xGe₁₃₆ Thin Films on Sapphire Substrates

〇Himanshu Shekhar Jha¹, N. Sugii¹, F. Ohashi¹, T. Kume¹, T. Mukai¹, T. Ban¹, S. Nonomura¹ (1.Gifu University)

Keywords:clathrate

Ge type II clathrate Na_xGe₁₃₆ is a compound material that consists of a cage-like framework of group IV element of Ge (host) and alkali guest atom of Na. Inclusion of the guest atoms (Na) induces peculiar characteristics on clathrate materials. The clathrate with fully occupied cages by guest atom (x =24) shows metallic behavior. However, guest-free clathrates (x~0) is considered as an allotrope of Ge and behaves like as semiconductors with similar or wider direct band gap. In recent year, guest free type II clathrates of Ge, Si etc. have increasingly attracted attention for their applications in solar photovoltaic.