Back-gating effect of low-temperature GaAs on a pseudomorphic modulation-doped field-effect transistor

Low-temperature (LT) photoluminescence (PL) measurements on pseudomorphic modulation-doped transistors with a (LT) GaAs layer in the GaAs substrate have revealed the existence of a substrate voltage. The substrate voltage is manifested by a decrease in the PL transition energies of the quantum-well subbands due to the quantum confined Stark effect. Our results indicate that the substrate voltage is generated by the trapping of holes from the undoped molecular-beam-epitaxy-grown GaAs at the GaAs/LT GaAs interface by the high concentration of arsenic antisite defects in the LT GaAs layer.