Critical point energy as a function of electric field determined by electroreflectance of surface-intrinsic-n~(+) type doped GaAs

摘要

Electroreflectance of surface-intrinsic-n~(+) type doped GaAs has been measured over a various biased voltage. The spectra have exhibited many Franz-Keldysh oscillations (FKOs) above band gap energy E_(g). The electric field F and critical point energy E_(c) can be determined from the slope and intercept of FKOs fitting. Hence, we can obtain E_(c) as a function of F. In most of previous works, E_(c) is taken as E_(g). However, it was found that E_(c) increases with F in this work. In order to explain this, the gain of energy of electron and hole in F was discussed.