Preparation of InAs quantum dots on GaAs substrate by metal-organic vapor phase epitaxy using N2 as carrier gas

Self-assembled InAs quantum dots (QDs) were fabricated on GaAs [001] substrates by low pressure metal-organic vapor phase epitaxy (LP-MOVPE) using N₂ as carrier gas for the first time. The influence of growth temperature on the QD properties under N₂ ambient was investigated. Atomic force microscopy (AFM) and photoluminescence (PL) spectroscopy were used to study the structural and optical properties of the InAs QDs. Also the influence of buffer layer composition on the QD properties has been studied. The effects of growth temperature under N₂ carrier are nearly the same as those under H₂ carrier, i.e., islands size increases and density decreases with temperature. By using GaAsSb as the buffer layer, the islands show an improved size uniformity comparing with islands grown on GaAs and InGaAs. Finally, the room temperature PL spectrum of InAs QDs grown on a GaAs_0.9Sb_0.1 buffer layer shows an emission wavelength at 1.35μm with a FWHM of 102nm.