Photoluminescence properties of self-assembled InAs quantum dots grown on InP substrates by solid source molecular beam epitaxy

Self-organized InAs quantum dots (QDs) with different depositions grown on an InP (100) substrate were prepared by solid source molecular beam epitaxy at different temperatures. Photoluminescence (PQ measurements are used to investigate optical properties of the QDs. It is observed that the PL emiss ions of QDs with 10 Angstrom InAs deposition exhibit multiple peaks. Beside s emission from the QDs at lower energy, two or three additional peaks are observed. This behavior is attributed to wetting layers with various thickn esses caused by an As/P exchange reaction, and this reaction is enhanced by an increase of the growth temperature. The features of PL emission change dramatically for the samples with increased InAs deposition. The PL emissio n from the QDs decomposes into two Gaussian peaks, which are associated wit h emission from QDs with two different size distributions. Atomic force mic roscopy examination shows the bimodal size distribution branch. This observ ation of the QD size distribution is simply explained by the surface mass t ransfer. (C) 2001 American Vacuum Society.