Room-temperature lasing via ground state of current-injected vertically aligned InP/GaInP quantum dots

We report room-temperature injection lasing of self-assembled InP/GaInP quantum dots. Stimulated emission occurs via the ground state at λ=728 nm for cavities as short as 0.5 mm. Threshold current densities of 2.3 kA/cm2 and external differential quantum efficiencies of 8.5% have been measured for 2 mm long devices. Light output power as high as 250 mW without saturation effects can be reached in pulsed excitation. Analysis of temperature-dependent laser emission indicates the thermal coupling of charge carriers in different quantum dots at higher temperatures.