Optical Characteristics of InAs/InGaAsP/InP Self-Assembled Quantum Dots Emitting at 1.4–1.6 µm

InAs/InGaAsP quantum dots (QD) grown on InP substrates show strong photoluminescence (PL) signals, with peaks from 1.4 to 1.6 µm at room temperature. Time-resolved PL measurements reveal that carrier lifetimes are the same across the entire PL band at low temperature, as well as at room temperature. This is strong evidence that the PL originates from the inhomogeneously broadened states of well-isolated QDs even at room temperature. These good characteristics, with the availability of additional InGaAsP confinement layers of different band gaps, make the present QD system a good candidate for low threshold lasers at 1.5 µm.