Effect of annealing temperatures on properties of CuAlO2 films prepared by sol-gel method on 4H-SiC substrates

Abstract

CuAlO2 thin films were prepared on 4H-SiC and sapphire substrates by sol–gel method and subsequent annealing process. The influence of annealing temperature from 800 °C to 1100 °C in nitrogen atmosphere on crystal structure, surface morphology and optical properties of CuAlO2 films was systematically elaborated to understand the annealing behavior and promote the development of p-CuAlO2/n-4H-SiC heterojunction. X-ray diffraction, scanning electron microscopy, and Raman spectroscopy results show that at 1000 °C annealing temperature CuAlO2 is relatively pure and has a high degree of crystallization. In addition, the AFM results indicated that the annealing temperature has a significant indigenous effect on the surface roughness of the film. The transmittance results demonstrated that when the annealing temperature is high (above 1000 °C), the film has higher transmittance (70 %) in the visible region. Overall, the results show that an appropriate annealing temperature is beneficial to obtain high-quality CuAlO2 films on SiC substrate.