Optical properties of AlAs/GaAs quantum wells with antimony as a surfactant by solid source molecular beam epitaxy

The influence of antimony (Sb) incorporation on the optical properties of AlAs/GaAs quantum wells (QWs) grown by solid source molecular beam epitaxy (SSMBE) has been investigated by room- and low-temperature photoluminescence (PL) measurements. Various Sb fluxes are used in an growing AlAs barrier layer. The room- and low-temperature PL measurements showed that incorporation of a very small amount of Sb doping can decrease the PL linewidths and increase the PL intensity of AlAs/GaAs QWs drastically, which indicates that Sb improves the interface and crystal quality as both a surfactant and an isoelectronic dopant in AlAs. However, the PL intensity reduces, and full-width at half-maximum (FWHM) of QWs increases with the increase of Sb flux, indicating that a little high concentration of Sb incorporated into the alloy and degrades the interfacial and crystalline quality. It is attributed to the strain-induced defects in the barrier layers of AlAs. Moreover, we also use the infinite square potential well model to study the relation of the interface roughness and FWHM. (c) 2005 Elsevier B.V. All rights reserved.