Preparation of CuAlO₂ Thin Films by Sol-Gel Method Using Nitrate Solution Dip-Coating

¹ Department of Human Culture, Faculty of Human Studies, Ishinomaki Senshu University, Ishinomaki, Japan
² Department of Basic Science, Faculty of Science and Engineering, Ishinomaki Senshu University, Ishinomaki, Japan

^a ehara@isenshu-u.ac.jp
^* Corresponding author: ehara@isenshu-u.ac.jp

Abstract

CuAlO₂ thin films are prepared by sol-gel dip-coating followed by annealing in nitrogen atmosphere using copper nitrate and aluminum nitrate as metal source materials. X-ray diffraction (XRD) patterns show (003), (006) and (009) oriented peaks of CuAlO₂ at annealing temperature of 800 – 1000°C. This result indicates that the CuAlO₂ films prepared in the present work are c-axis oriented. XRD peak intensity increase with annealing temperature and becomes maximum at 850°C. The CuAlO₂ XRD peak decreased at annealing temperature of 900°C with appearance of a peak of CuO, and then increased again with annealing temperature until 1000 °C. The films have bandgap of 3.4 eV at annealing temperature of 850°C in which the transparency becomes the highest. At the annealing temperature of 850°C, scanning electron microscope (SEM) observation reveals that the films are consist of amorphous fraction and microcrystalline CuAlO₂ fraction.