Electrical and structural characterization of Zn doped CuGaO2 films

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 V_g proved the hole dominated transport properties. The curve in the positive gate bias can be suppressed by introducing Zn.