Raman and photoluminescence studies of transitions of quantum‐confined acceptors

Abstract

The internal transitions of Be acceptors confined in the center of GaAs/AlAs multiple quantum wells are investigated by Raman and photoluminescence (PL) spectra. A series of Be d-doped GaAs/AlAs multiple quantum wells with doping at the well center and well widths ranging from 30 to 200 Å were grown on (100) GaAs substrates by molecular beam epitaxy. Both the Raman and PL spectra were measured at 4 and 20 K, respectively. The confined longitudinal optical (LO) modes, and transitions of Be acceptors from the 1S 3/2 (G 6 ) ground state to 2S 3/2 (G 6 ) first excited state were clearly observed in Raman spectra. Two-hole transitions of the acceptor-bound excitons from the 1S 3/2 (G 6 ) ground state to the 2S 3/2 (G 6 ) first excited state were also observed. It is found that the experimental results in the Raman spectra are close to those measured in the PL experiments.

Excitonic transitions in Be-doped GaAs/AlAs multiple quantum well

“…Quasi-two-dimensional semiconductor-based quantum well and superlattice structures have extensively been investigated because of their potential applications in compact Terahertz emitters, cascade lasers, small-size detectors, etc. [1][2][3][4][5] A characteristic feature of the optical spectra of quantum well and superlattice systems at low temperatures is the occurrence of excitons. The exciton is often treated as a 'two-body' combination involving an electron and a hole between which there is Coulombic interaction.…”