Photo Detachment of Negatively Charged Muonium in GaAs by Laser Irradiation

Abstract Photo detachment of negatively charged muonium was successfully observed the first time, with wide range wave length from 800 nm to 1450 nm lasers in n-type GaAs at 15 K. Recently, Lichti et al . determined the energy levels in the band gap of T center muonium (as an acceptor) and BC muonium (as a donor) by reanalysis of the existing data obtained by various μSR techniques for several semiconductors like Si, Ge, GaAs, GaP etc. In these semiconductors, GaAs is one of the best sample to apply the negatively charged muonium photo detachment method, because the energy level of T center muonium is above 0.54 eV from the valence band, therefore the ionization energy for Mu T - → Mu T 0  + e - is 0.98 eV (corresponding laser wave length is 1260 nm), which is within the region of present OPO laser system produced, which was installed RIKEN-RAL