Structure and photoluminescence properties of epitaxial SnO2 films grown on α-Al2O3 (0 1 2) by MOCVD

SnO2 thin films have been successfully deposited on α-Al2O3 (0 1 2) substrates by metalorganic chemical vapor deposition (MOCVD) in the temperature range 500-700 °C. The films were epitaxially grown in the tetragonal SnO2 phase and were (1 0 1) oriented. In-plane orientation relationship [0 1 0]SnO2||[1 0 0]Al2O3 and [1 0 1̄]SnO2||[1̄ 2̄ 1]Al2O3 was determined between the film and substrate. Photoluminescence (PL) spectra measured at room temperature revealed that the film grown at 700 °C showed an intense ultra-violet (UV) PL peak at 333 nm, which was a band-edge emission peak in SnO2 films. At a temperature of 13 K, a new broad PL band centered at about 480 nm was observed. The corresponding PL mechanisms are discussed in detail.