Advancing THz spectroscopy
Low temperature GaAs (LT-GaAs) is usually grown by molecular beam epitaxy (MBE) at substrate temperatures ranging from 200°C to 350°C. Due to the low growth temperature (compared to conventional GaAs wich is grown at 600°C-650°C), LT-GaAs is highly nonstoichiometric, with a large density of excess arsenic incorporated into the GaAs matrix forming a high concentration of deep-level defects. These defects result in very short carrier lifetime, necessary for applications demanding ultra-fast signal switching. Examples of these are devices for terahertz (THz) sensors and imaging systems, such photoconductive antenna chips (PCA). In collaboration with TeTech, we are developing LT-GaAs based PCAs with high performance and efficiency for advanced THz spectroscopy systems.