Excited states of shallow acceptors confined in GaAs/AlxGa1-xAs quantum wells.

Abstract

An optical study of the excited states of shallow acceptors confined in narrow GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As quantum wells (QW's) is presented. The excited states have been investigated via the two-hole transitions (THT's) of the bound exciton recombination observed in selective photoluminescence (SPL) and photoluminescence excitation (PLE) spectroscopy. Several heavy-hole (hh) -like excited nS(${\mathrm{\ensuremath{\Gamma}}}_{6}$) acceptor states dominate the satellite spectrum, but also the light-hole (lh) -like excited 2S(${\mathrm{\ensuremath{\Gamma}}}_{7}$) acceptor state has been observed in these SPL spectra. In addition, the THT corresponding to the parity-forbidden transition to the 2${\mathit{P}}_{3/2}$ excited state has been observed. When detecting any of the THT satellites corresponding to the 2S acceptor state, the 1S(${\mathrm{\ensuremath{\Gamma}}}_{6}$) hh-like acceptor ground state has been spectrally resolved from the 1S(${\mathrm{\ensuremath{\Gamma}}}_{7}$) lh-like acceptor state in PLE spectra. Together with the previously published results for the p-like excited states, these data complete the electronic structure of shallow acceptors in a QW.