Effects of post-growth annealing on the structure and electro-optical properties of low-temperature grown GaAs

This paper investigates how postgrowth annealing affects the structure and the electro-optical properties of low-temperature grown GaAs (LT-GaAs). A systematic study of as-grown and annealed LT-GaAs revealed that the carrier lifetime is directly related to the density of the An duster and distance between As clusters. The Ga/As compositional ratio and the crystal structure of As clusters were observed for the first time. The As/Ga ratio of the As clusters is higher than that obtained from the LT-GaAs. The carrier lifetime of the annealed LT-GaAs increases as the annealing temperature increases from 400 (less than 30 fs) to 800 °C (824 fs). Under the annealing temperatures ranging from 600 to 700 °C for 90 s, we observed the emission of terahertz radiation using the annealed LT-GaAs grown at temperatures ranging from 260 to 320 °C.