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.