Excitation-intensity-dependent photoluminescence in semiconductor quantum wells due to internal electric fields

Abstract

Low-temperature photoluminescence (PL) has been studied in several III-V single-quantum-well (SQW) samples. We have observed shifts of the PL peak energy as a function of the excitation intensity which, we show, are due to the quantum confined Stark effect (QCSE) caused by the internal electric field at the surface and/or heterointerfaces in the samples. The experimentally measured PL peak shifts in ${\mathrm{In}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As/GaAs and ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As/GaAs SQW's are compared with calculations based on the QCSE and excellent agreement is found. The magnitude of the internal field determined from the PL analysis coincides with the value for the electric field obtained from photoreflectance measurements on the same samples, at the same temperatures. \textcopyright{} 1996 The American Physical Society.