Bound phonons and DX centers in GaAs under hydrostatic pressure.

Abstract

Raman scattering experiments performed on n-type doped GaAs samples as a function of hydrostatic pressure reveal the existence, at low temperature and beyond some critical value of the pressure, of bound phonons associated with electrons trapped at an effective-mass-like level. At higher temperatures, this level is depopulated to the benefit of a deep state which has all the characteristics of the DX center. These results indicate a shallow-deep bistable character of n-type impurities in GaAs under high pressure.