Growth and Characterization of Sn Doped β-Ga2O3 Thin Films and Enhanced Performance in a Solar-Blind Photodetector

Ga 2− x Sn x O 3 thin films were deposited on c -plane Al 2 O 3 (0001) substrates with different Sn content by laser molecular beam epitaxy technology (L-MBE). The Sn content x was varied from 0 to 1.0. ( 2 ¯ 01 ) oriented β -phase Ga 2− x Sn x O 3 thin films were obtained at the substrate temperature of 850°C in the vacuum pressure of 5 × 10 −5 Pa. The crystal lattice expanded and the energy band-gap decreased with the increase of Sn content for Sn 4+ ions incorporated into the Ga site. The n -type conductivity was generated effectively through doping Sn 4+ ions in the Ga 2 O 3 lattice in the oxygen-poor conditions. The solar-blind (SB) photodetectors (PDs) based on Ga 2− x Sn x O 3 ( x = 0, 0.2) thin films were fabricated. The current intensity and responsivity almost increased by one order of magnitude and the relaxation time constants became shorter for x = 0.2. Our work suggests that the performance of PD can be improved by doping Sn 4+ ions in Ga 2 O 3 thin films.