Interactions between DX centers and hot electrons and holes in AlGaAs/GaAs heterostructure field-effect transistors

Using power Al0.25Ga0.75As/GaAsAl0.25Ga0.75As/GaAs heterostructure field-effect transistors (HFETs) and both electrical and electroluminescence measurements, we show here that while at room temperature the electron and hole capture processes at the DX centers present in the AlGaAs are in equilibrium, and therefore no charge buildup leading to drifts in the HFET characteristics may take place, under cryogenic conditions (T<100 K), where the electron and hole capture cross sections of the DX centers are very different, two competing processes of hole and hot electron capture lead to bias-dependent, negative, recoverable HFET threshold voltage shifts.