A study of Ga0.75Al0.25As/GaAs heterostructures showed that, at room temperature, the electron and hole capture processes at the DX centers were in equilibrium. Therefore, no charge build-up could take place at temperatures below 100K. Here, the electron and hole capture cross-sections of the DX centers were very different.

Interactions between DX centers and hot electrons and holes in Al0.25Ga0.75As/GaAs heterostructures D.Dieci, C.Canali, R.Menozzi, M.Pavesi, A.Cetronio: Applied Physics Letters, 1999, 74[8], 1147-9