Raman scattering of polycrystalline GaSb thin films grownby co-evapouration process

This paper reports that GaSb thin films have been co-deposited on soda-lime glass substrates. The GaSb thin film structural properties are characterized by Raman spectroscopy. The Sb--A_1g/GaSb--TO ratio decreases rapidly with the increase of substrate temperature, which suggests a small amount of crystalline Sb in the GaSb thin film and suggests that Sb atoms in the thin film decrease. In Raman spectra, the transverse optical (TO) mode intensity is stronger than that of the longitudinal optical (LO) mode, which indicates that all the samples are disordered. The LO/TO intensity ratio increases with increasing substrate temperature which suggests the improved polycrystalline quality of the GaSb thin film. A downshift of the TO and LO frequencies of the polycrystalline GaSb thin film to single crystalline bulk GaSb Raman spectra is also observed. The uniaxial stress in GaSb thin film is calculated and the value is around 1.0~GPa. The uniaxial stress decreases with increasing substrate temperature. These results suggest that a higher substrate temperature is beneficial in relaxing the stress in GaSb thin film.