Optical properties of p-type modulation-doped InAs quantum dot structures grown by molecular beam epitaxy

We have performed temperature-dependent studies of photoluminescence, (PL) properties of p-type modulation-doped InAs/GaAs quantum dots (QDs) structures grown by molecular beam epitaxy. In temperature dependence of integrated PL intensity, full width at half maximum (FWHM) of PL spectra and its peak energy, differences between undoped and p-doped have depended on a modulation-doping level. We have observed the improvement of temperature stability of PL intensity by p-type modulation doping to InAs QDs in comparison with that of undoped. FWHM of PL spectrum of p-InAs QDs increases as modulation-doping level increases. Excessive modulation doping has caused the degrading of PL properties due to Beryllium (Be) diffusion from p-GaAs modulation-doping layer to InAs layer via undoped GaAs spacer layer. The Be diffusion into InAs region was confirmed by secondary ion mass spectroscopy. (c) 2006 Elsevier B.V. All rights reserved.