Photoluminescence study of InAs/GaAs self-organized quantum dots with bimodal size distribution

We have investigated the temperature dependence of the photoluminescence (P L) spectrum of self-organized InAs/GaAs quantum dots. A distinctive double- peak feature of the PL spectra from quantum dots has been observed, and a b imodal distribution of dot sizes has also been confirmed by scanning tunnel ing microscopy image for uncapped sample. The power-dependent PL study demo nstrates that the distinctive PL emission peaks are associated with the gro und-state emission of islands in different size branches. The temperature-d ependent PL study shows that the PL quenching temperature for different dot families is different. Due to lacking of the couple between quantum dots, an unusual temperature dependence of the linewidth and peak energy of the d ot ensemble photoluminescence has not been observed. In addition, we have t uned the emission wavelength of InAs QDs to 1.3 mu m at room temperature.