Effect of the built-in electric field on optical and electrical properties of AlGaAs/InGaAs/GaAs P-HEMT nanoheterostructures

This study is concerned with the photoluminescence spectra and electrical parameters of AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistor (P-HEMT) structures with a quantum well grown at different depths $L_b$ with respect to the surface. The samples are produced so as to make the concentration of electrons in the quantum well unchanged, as the barrier layer thickness $L_b$ is reduced. It is established that the photoluminescence spectra of all of the samples exhibit peaks at the photon energies $\hbar\omega$ = 1.28–1.30 and 1.35–1.38 eV. The ratio between the intensities of these peaks increases as $L_b$ is decreased. Calculations of the band structure show that variations in the spectra are due to the fact that the built-in electric field increases as the quantum well is set closer to the surface.