Temperature Dependence of CuGaO 2 Films Fabricated by Sol–Gel Method

P-type CuGaO 2 films have been fabricated on silicon substrates by the sol–gel method. The stable sol solutions for CuGaO 2 growth were developed by the mixing of Cu–O and Ga–O sol solutions using copper(II) acetate monohydrate and tris(acetylacetonato) gallium(III), respectively. Phase separation in CuGaO 2 films depends on the sol solution temperature and postbake temperature and duration. CuGaO 2 films without a CuO phase were fabricated by postbaking at temperatures of approximately 800 °C for 1 h in N 2 atmosphere. The sol–gel-derived CuGaO 2 films show high transparency of more than 80% in the visible range, and the energy gap is approximately 3.6 eV.