A monolithic InGaN/GaN disk-in-nanowire electrically pumped edge-emitting green (λ=533 nm) laser on (001) silicon

Abstract

Silicon photonics has assumed an increasing degree of importance due to the necessity of realizing photonic components, and ultimately optical communication systems, on silicon CMOS chips. While silicon based detectors, waveguides, and modulators have emerged with superior levels of performance, the demonstration of a suitable electrically pumped monolithic laser on (001) Si substrate has remained elusive. GaAs-based quantum well and quantum dot lasers, emitting in the wavelength range of 1.0-1.3 μm have been reported by us and others, but these devices have to be grown on misoriented substrates [(001)→4° towards (111)] to prevent antiphase domains. The large lattice mismatch induced dislocation density makes the long term reliability questionable. III-V based lasers bonded on silicon substrates is another technology that has been pursued with some degree of success. Growth on miscut substrates and with novel buffer layers have been investigated. Ga(In)N nanowires and InGaN/GaN disk-in-nanowire heterostractures can be grown relatively free of extended defects on (001) Si. The nanowires grow in the wurtzite crystalline form along the c-axis. Due to the radial relaxation of strain during epitaxy, the polarization field in the heterostractures is very small, compared to quantum wells. The surface recombination velocity on the nanowire sidewalls is ~ 103 cm/s. Emission in the range of 400-700 nm for InGaN nanowires and InGaN/GaN disks has been demonstrated. We demonstrate here, for the first time, the characteristics of a monolithic InGaN/GaN disk-in-nanowire room temperature electrically injected edge-emitting green laser (λ=533nm) on (001) Si. Nanowire lasers emitting at longer or shorter wavelengths can also be realized by varying the In content in the InGaN disks.