MBE growth of single crystalline AlInAs/GaInAs MQWs at the low growth temperature limit

摘要

Single crystalline AlInAs/GaInAs multiple quantum wells (MQWs) were grown by MBE at growth temperatures (T_g) ranging from 550 deg C down to 100 deg C. High structural quality was ascertained for all samples from X-ray diffraction (XRD) measurements. Room temperature (RT) photoluminescence (PL) signals were monitored down to T_g = 150 deg C. With decreasing T_g a blueshift of the emission by 30 meV was observed, as also confirmed by RT absorption measurements. This blueshift is referred to two-dimensional (2D) band filling due to an increase of the residual free electron concentration of more than two orders of magnitude at low T_g, which in turn is responsible for the significant weakening of excitonic features in the absorption spectra.