Photoluminescent properties of Cd_xZn_1-xO thin films prepared by sol-gel spin-coating method

Cd_xZn_1-xO thin films were prepared on Si (100) substrates by the sol-gel spin coating method. Temperaturedependent photoluminescence (PL) measurements were carried out to investigate the luminescent properties of the Cd_xZn_1-xO thin films. The PL peaks of the Cd_xZn_1-xO thin films decrease as the Cd concentration increases and the near-band edge emission (NBE) PL peaks of the Cd_xZn_1-xO thin films are shifted toward the red region. In the temperature-dependent PL measurement, three components at 2.855, 3.038, and 3.148 eV in the PL emission peak of the Cd_0.2Zn_0.8O thin films were observed at 12 K. With increasing temperature, the emission peak at 3.148 eV at 12 K becomes red-shifted and the monotonic PL peak at 12 K divides into three clear peaks as the temperature increases. The activation energy for the 3.148 eV peak is 69.54 meV corresponding to the energy for the frozen-out donors.