Ultrafast carrier response of Br+-irradiated In0.53Ga0.47As excited at telecommunication wavelengths

摘要

We present results of infrared pump—terahertz probe experiments applied to a set of In0.53Ga0.47As films irradiated with heavy ions (Br+) at doses from 109 to 1012 cm-2. Photoexcitation at 1400 nm (0.89 eV) allowed us to characterize the response close to telecommunications’ wavelengths whilst avoiding the intervalley carrier scattering observed when a shorter wavelength excitation is used. The excitation fluence was varied in our experiments in order to characterize the dynamics in detail: the lifetimes and mobilities of both electrons and holes were retrieved, and the trap filling and carrier diffusion were clearly observed. The In0.53Ga0.47As film irradiated by the dose of 1012 cm-2 exhibits simultaneously ultrashort electron lifetime (∼300 fs) and very high electron mobility (2800 cm2V-1s-1). These findings are particularly important for the design of terahertz emitters controlled by lasers operating at standard telecommunication wavelengths.