Photoluminescence spectroscopy of growth-interrupted GaAs/AlAs single quantum wells subjected to hydrogenation

Abstract

Photoluminescence excitation and emission spectroscopy (PLE and PL) have been used to investigate growth interrupted GaAs/AlAs single quantum wells (SQW). Evidence that growth interruption leads to smooth interfaces which vary in height by integer monolayer steps is provided by changes in the PLE and PL spectra from a broad single band for noninterrupted SQW to narrow multiple peak features for growth interrupted samples. However, growth interruption results in a dramatic reduction in the intensity of the photoluminescence signal above 30 K. Hydrogenation treatment has been found to recover the photoluminescence intensity in the growth-interrupted samples which we attribute to passivation of nonradiative centers incorporated during the growth interruption process. Similar, though less dramatic, effects have been observed for noninterrupted samples. Time-resolved photoluminescence spectroscopy and decay time measurements show that hydrogen passivates carbon acceptors also incorporated during interruption, and in addition, demonstrate the migration process of excitons from the narrower to the wider well widths in these SQW. This latter exciton kinetic information fully supports the view that growth interruption results in large lateral islands with monolayer fluctuations in well width.

Realistic heterointerface model for excitonic states in growth-interrupted GaAs quantum wells

“…This is actually supported by previous experiments. Yu et al 18 have studied the PL spectra of GaAs/AlAs QWs depending on the GI time. They observe (Fig.…”

Exciton migration and recombination enhancement in GaAs/AlAs single quantum wells under resonant excitation

“…(A different point on the wafer to that of fig. 2 has been used and the variation is due to a different average thickness [4].) Under resonant excitation of 22 ML peak there is a x 20 enhancement in the PL intensity for the 22 ML and a x 15 for the 23 ML peaks as shown in fig.…”

Effect of hydrogen on modulation-doped AlGaAs/InGaAs/GaAs heterostructures: a photoluminescence study

“…It is well known that hydrogen in bulk samples as well as in quantum well (QW) structures saturate the dangling bond, passivates both shallow dopants and deep centers by forming hydrogen impurity complexes [1][2][3][4][5][6][7]. Gal et al [8] observed the neutralization of interface defects caused by misfit dislocations, in partially relaxed In y Ga 1Ky As/GaAs heterostructures by hydrogen plasma.…”