[18a-Z33-1~9] 21.1 Joint Session K "Wide bandgap oxide semiconductor materials and devices"

[18a-Z33-6] Insulating-Degenerated-Insulating transition observed in electrical properties of mixed anion layered compounds, LaCu_1-δS_0.5Se_0.5O (δ=0-0.02)

〇Yoichi Kamihara^1,3, Nobuhiko Azuma¹, Ryosuke Sakagami¹, Hidetomo Usui² (1.Dep.APPI, Keio Univ., 2.Shimane Univ., 3.CSRN, Keio Univ.)

Keywords:mixed anion, degenerated semiconductor, Cu deficient

We synthesized several nominal LaCu_1-δS_0.5Se_0.5O (δ=0, ~0.01, and ~0.02). Polycrystalline mixed anion layered compounds (MALC) LaCu_1-δS_0.5Se_0.5O (δ~0.01) is a degenerated semiconductor at temperatures > 300 K. p-type carriers were originated from Cu deficient Cu_1-δS_0.5Se_0.5 layers. In-gap states, which dominate electrical conduction, are observed at energy ~0.5 eV higher than that of the valence band in an energy band diagram for δ~0.01.