Role of inserting layer controlling wavelength in InGaAs quantum dots

Emission wavelength from the self-assembled In(Ga)As QDs on GaAs is typically around 1.0 /spl mu/m. In order to be applied to optical fiber communication, the extension of its optical emission wavelength to 1.3 /spl mu/m and further is necessary. Several groups have demonstrated GaAs-based InGaAs QDs with 1.3 /spl mu/m photoluminescence (PL). During the formation of such ternary dots, the variation of composition and dot size make it difficult to reproducibly achieve long wavelength emission. Long emission wavelength up to 1.3 /spl mu/m at room temperature cannot be realized until the In(Ga)As dots are placed in or below and InGaAs matrix. Among the proposed origins of achieving long wavelength emission from InAs quantum dots, we believe that the residual strain in quantum dots plays a key role. In this study, we have investigated the role of inserting layers tuning emission wavelength in InGaAs quantum dots.