Photoinduced band-bending effect of low temperature GaAs on AlGaAs/InGaAs/GaAs modulation-doped transistors

Low temperature photoluminescence (PL) measurements on pseudomorphic modulation-doped transistors (PHEMTs) with a low-temperature (LT) GaAs layer in the GaAs buffer layer clearly show a decrease in the quantum well PL transition energies compared to a PHEMT with no LT GaAs. Self-consistent calculations of the quantum well PL transition energies and oscillator strengths show that the observed decrease in PL energies can be attributed to a larger photoinduced band bending in PHEMTs with an undoped GaAs/LT GaAs interface compared to the photoinduced band bending in PHEMTs with an undoped GaAs/semi-insulating GaAs interface.