What Is the Longest Lasing Wavelength of InAs/InP (100) Quantum Dots Grown by Metal Organic Vapor Phase Epitaxy?

The longest lasing wavelength of InAs/InGaAsP/InP (100) quantum dots (QDs) is hampered by the QD emission blueshift upon growth of the upper laser structure. The authors investigate this blueshift in photoluminescence (PL) for growth by metal organic vapor phase epitaxy. For the same InAs QD growth temperature, the PL blueshift increases with reduced growth temperature of the upper laser structure and with the Ga composition of the QD cap layer, accompanied by PL intensity decrease. Hence, In-Ga intermixing assisted by defects in the matrix diffusing towards the QDs causes the blueshift. The longest lasing wavelength of InAs/InP QDs grown by metal organic vapor phase epitaxy is 1.95 mu m for operation in continuous wave mode at room temperature. To achieve long-wavelength mid-infrared emission from InAs/InP QD lasers, particular care has to be taken with optimizing the growth conditions of the waveguide and cladding layers. (C) 2010 The Japan Society of Applied Physics