Electrical and structural characterization of Zn doped CuGaO2 films

Abstract

Oxide materials have been widely used in opto-electro devices due to their wide bandgap energy, high optical transparency in the visible light region, and wide range resistance. Recently, delafossite CuMO2 (M=Al, Ga, In) have been widely studied for p-type oxide semiconductors. In this study, CuGaO2 was chosen due to its smaller lattice mismatch with ZnO compared with CuAlO2 for the possibility of p-n junction device in the future work. Zn as impurity atoms was introduced to fabricate quaternary CuZnGaO2 films to reduce lattice mismatch with ZnO. In order to study the effect of the substitute site of the Zn ion for generating donor or acceptor, 3 methods of preparation of the Cu-Zn-Ga-O sol solution were also demonstrated. In this paper, the electrical and structural properties of Zn doped on the sol-gel derived CuGaO2 films have been investigated. The diffraction angle of the CuGaO2 films are shifted to lower angle with increasing Zn%, indicating the lattice expansion which proved that the introducing Zn as impurity atoms was able to reduce lattice mismatch between CuGaO2 and ZnO. While the curve in the negative gate bias Vg proved the hole dominated transport properties. The curve in the positive gate bias can be suppressed by introducing Zn.