Preparation of CuYO 2 Thin Films by Sol-Gel Method Using Copper Acetate and Yttrium Acetate as Metal Sources

Abstract

Delafossite structured p-type wide bandgap semiconductor, CuYO2 thin films were prepared on SiO2 substrate by sol-gel method using copper (II) acetate and yttrium (III) acetate as source materials. The films preparation process was studied by varying annealing temperature after the preparation of gel films by spin coating, followed by thermal annealing at higher temperature. In the present work, one step annealing directly from Cu-Y-gel under nitrogen flow was used. X-ray diffraction (XRD) revealed that the film annealed at 800˚C is significantly c-axis oriented, shows only (002) and (004) peaks at 15.6˚ and 31.5˚, respectively. The optical bandgap of 3.7 - 3.8 eV is estimated by (αhν)2 plot which is higher than previous works. In addition, the films with highly c-axis orientation showed photoluminescence (PL) at room temperature with very broad peak at 2.3 eV. The films annealed at different temperature showed different structural properties.