III–V lasers selectively grown on (001) silicon

Epitaxial growth of III–V lasers on the (001) Si platform is emerging as the ultimate integration strategy for low-cost, energy-efficient, and wafer-scale photonic integrated circuits. As the performance of laser diodes grown on III–V/Si compliant substrates develops toward commercialization, the issue of light interfacing between epitaxial III–V lasers and Si-based waveguides is becoming increasingly pressing. As an alternative, selective area growth produces buffer-less III–V lasers on Si and thereby intrinsically promotes efficient light coupling with Si-photonics. As the dimension of the selectively grown dislocation-free III–V crystals is often limited at the sub-wavelength scale, the main challenge lies at the realization of electrically driven lasers and, specifically, at how to pattern the metal contacts without inducing large optical absorption loss. In this Perspective, we provide a brief overview of the state-of-the-art III–V lasers selectively grown on the (001) Si platform and discuss the outlook of this integration approach with an emphasis on the prospects of achieving electrically driven devices. We focus on the unique advantages offered by selective hetero-epitaxy as well as the challenges and potential solutions toward practical applications.