Fabrication of bipolar CuInO 2 with delafossite structure

Abstract

The crystal structure, electrical behaviors and band structure of new delafossite-type CuInO 2, which was newly synthesized in our previous study, were investigated to compare with those of isostructural CuAlO 2. The structure of CuInO 2 is rhombohedral, and its lattice parameters are larger than those of CuAlO 2. CuAlO 2 shows both p-type semiconductor with a conductivity of 6.7×10 −5 S m −1 at 600 K, which is smaller than that (9.4×10 −2 S m −1) of CuAlO 2, and n-type semiconductor with a conductivity of 4.4×10 −1 S m −1 at 600 K. The band structure calculations based on the density functional theory indicate that CuInO 2 is a semiconductor having a 0.49 eV indirect band gap. The bands lying near the Fermi level of CuInO 2 are mainly made up from the Cu-3d and O-2p wave functions.