Charge States of DX Centers and Electronic Raman Scattering in n-Ga_1-xAI_xAs

The observation of the electronic Raman scattering in n-Ga_l-xAI_xAs (x > 0.45) is reported and the charge state of DX centers in III-V alloy semiconductors is discussed. The result shows clearly that the electronic Raman scattering in n-Ga_l-xAI_xAs of indirect band-gap and the persistent photoconductivity in n-Ga_l-xAI_xAs of direct band-gap are equivalent to each other. Both of them originate from the optical induced metastable state of donors in n-Ga_l-xAI_xAs (x > 0.22) at low temperatures. At higher temperatures, this hydrogen-like level is depopulated to the benefit of a stable DX-like deep state.