Broadening of Photoluminescence by Nonhomogeneous Size Distribution of Self-Assembled InAs Quantum Dots

The photoluminescence spectrum (PL) of InAs quantum dots (QDs) at 80K is studied by comparison between the theoretical calculation and experimental measurement. The Gaussian line shape is used to approximate the size distribution of QDs. Its mean volume and the standard size deviation are well correlated with the peak and full width at half maximum (FWHM) of the PL spectrum. The experimental PL spectrum is well reproduced by the theoretical model based on the effect mass approximation including the size distribution without any adjustable parameters. Compared with the standard size deviation value σ_s=9×10^-2 determined by atomic force microscopic method a small value σ_s=7×10^-2 is obtained by the best fitting process from the measured and calculated PL spectra