Temperature dependent photoluminescence of self-organized InAs quantum dots on an InGaAs strain buffer layer grown by MOCVD

In this article, we investigate the formation and optical properties of 3-monolayer (ML) InAs quantum dots (QDs) on the InGaAs strain buffer layer (SBL) grown by metallorganic chemical vapor deposition (MOCVD). As compared to the InAs QDs directly grown on a GaAs surface, the InAs QDs grown on an InGaAs SBL can increase the dot density from 1.7 to 3.5 x 10(10) cm(-2) and improve the uniformity. Using microphotoluminescence (mu-PL) measurements, the power-dependent PL at low temperatures shows the ground, first, and second states of InAs QDs due to the state-filling effect at the highest excitation power density of 11900 W/cm(2). The temperature-dependent PL spectra shows that the PL peak energy has a redshift following the Varshni relation and an unusual temperature dependence of the linewidth, which first reduces and then increases with temperature for the InAs QDs grown on the InGaAs SBL. The PL thermal quenching is determined by the carrier escape from the QDs to the nonradiative recombination centers. The peak wavelength and full width at half maximum of PL spectra at 280 K for the InAs QDs grown on an InGaAs SBL are 1306 nm and 21.5 meV, respectively. (c) 2007 The Electrochemical Society.