Optical characteristics of self-assembled InAs quantum dots with InGaAs grown by a molecular beam epitaxy

Self-assembled InAs quantum dots (QDs) with In_0.15Ga _0.85As were grown by a molecular beam epitaxy and their optical properties were investigated by photoluminescence (PL) spectroscopy. For InAs QDs inserted in an asymmetric In_0.15Ga_0.85As quantum well, the emission peak position of QDs is 1.30μm (0.953eV) with narrower PL linewidth and larger energy-level spacing between the ground states and the first excited states compared to those of QDs embedded in a GaAs matrix. While the room temperature PL yield for InAs QDs in a GaAs matrix was reduced by 1/99 from that measured at 18K, the reduction in PL yield for InAs QDs, grown on a 1nm In_0.15Ga_0.85As layer, with a 6nm In _0.15Ga_0.85As overgrowth layer was only 1/27. Also, using the In_0.15Ga_0.85As overgrowth layer significantly reduced the temperature sensitivity of the peak energy for InAs QDs. The relatively better temperature PL characteristics of the QDs with In_0.15Ga _0.85As, as well as the ability to control the emission peak position and the energy-level spacing are interesting and important for device applications.