Low-threshold buried-ridge II-VI laser diodes

Abstract

Blue‐green (λ=511 nm) separate confinement laser structures based on lattice‐matched MgZnSSe‐ZnSSe‐CdZnSe have been grown by molecular beam epitaxy. Wide stripe gain‐guided devices have been fabricated from several such wafers. These devices exhibit room‐temperature pulsed threshold current densities as low as 630 A/cm² and threshold voltages less than 9 V. Using a novel self‐aligned process that results in a planar surface, buried‐ridge laser diodes have also been fabricated. These devices have demonstrated room‐temperature threshold currents as low as 2.5 mA, which is more than a factor of 50 lower than that of any previously reported II‐VI laser diode. Room‐temperature operation at duty factors up to 50% has been demonstrated. The far‐field patterns from these devices indicate single lateral mode operation, suitable for diffraction‐limited applications, such as optical data storage.