InP quantum dots for dislocation-tolerant, visible light emitters on Si

Abstract

Quantum dots (QDs) epitaxially grown on Si are promising for monolithic integration of light sources on a Si photonics platform. Unlike quantum well (QW) lasers on Si, 1.3 μm InAs QD lasers on Si show similar threshold current to those grown on GaAs owing to their better dislocation tolerance. To date, research on dislocation-tolerant QDs has exclusively focused on materials emitting at telecom wavelengths. In this work, we report visible InP QDs on Si with photoluminescence (PL) intensity similar to their counterparts grown on GaAs despite high threading dislocation density (TDD). In contrast, visible InGaP QWs grown on Si with the same TDD value show 9× degradation in PL intensity compared to QWs grown on GaAs. The dislocation tolerance of InP QDs arises from their high density relative to TDD and the lateral carrier confinement that they provide. InP QDs on Si with bright PL are promising for low-cost light emitters and integrated photonics applications requiring monolithic red-light sources.