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

Abstract

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 1.30 μm (0.953 eV) 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 18 K, the reduction in PL yield for InAs QDs, grown on a 1 nm In 0.15Ga 0.85As layer, with a 6 nm 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.