Investigation of the effects of growth temperature on the photocarrier density of low-temperature grown gallium arsenide photoconductive antenna

Abstract

We investigated the effects of varying the substrate growth temperatures (T_g) on the carrier density and its temporal change in low-temperature grown gallium arsenide (LT-GaAs) photoconductive antenna (PCA). Increasing T_g results to a higher crystalline quality, leading to higher carrier densities, ranging from from 1.51x10²⁴ m^–3 at 200^∘C to 2.50x10²⁴ m^–3 at 320^∘C. However, the carrier density saturates in the region of 260^∘C, indicating optimal performance within a T_g range of 200^∘C to 260^∘C. Moreover, decrease in the growth temperature leads to an increase in the defect concentration which results to a decrease in the carrier lifetime, consequently decreasing carrier densities from 2.55x10²⁴ m^–3 at 1.17x10^–17 m^–3 to 1.50x10²⁴ m^–3 at 1.57x10^–17 m^–3. These results provide significant insights into the optimization of temperature growth, and doping concentrations parameters in LT-GaAs growth for PCA fabrication and possible THz technology applications.