Properties of RF sputtered CdS thin films

CdS thin films have been prepared using RF sputtering in an Ar atmosphere. X-ray diffraction studies showed that the films have hexagonal structure with crystallites preferentially oriented in the [002] direction. The crystallite size determined from the broadening of the [002] peak was found to increase with film thickness. The results of electrical conductivity measurements on films with different thickness suggest that the crystallites are undepleted above a thickness of about 500 nm and partially depleted below that value. The intergrain barrier height was determined to be in the range 0 to 0.15 eV in the studied samples. The energy band gap was determined from optical absorption data to be 2.46±0.01 eV for the studied films. From the temperature dependence of the electrical conductivity, activation energies in the range 0.12-0.21 eV were determined which agree with previously reported values.