Structural and optical characterization of single-phase γ-In2Se3 films with room-temperature photoluminescence

The single-phase γ-In2Se3 films with red room-temperature photoluminescence (PL) have been realized by atmospheric metal-organic chemical vapor deposition at the temperature range of 350-500 °C. The crystal structure of the γ-In2Se3 films was determined by X-ray diffraction and Raman spectroscopy. From the temperature dependence of the free exciton line, the room-temperature energy gap of γ-In2Se3 films is found to be about 1.947 eV. At 10 K, the free exciton emissions was observed and located at 2.145 eV. The temperature dependence of the near band-edge emission in the temperature region of 10-300 K has been investigated. The measured peak energy of near band-edge emission redshifts by about 200 meV with increasing temperature from 10 to 300 K, and is expressed by, Eg(T) = 2.149 + ((−8.50 × 10−4)T2/(T + 75.5)) eV. This study was done to complete the reported information about γ-In2Se3 thin films.