Performance improvement of InGaN-based laser grown on Si by suppressing point defects

High performance InGaN-based laser diodes (LDs) monolithically grown on Si is fundamentally interesting and highly desirable for photonics integration on Si platform. Suppression of point defects is of crucial importance to improve the device performance of InGaN-based LDs grown on Si. This work presents a detailed study on the impact of point defects, such as carbon (C) impurities and gallium vacancies (V_Ga), on the device characteristics of InGaN-based LDs grown on Si. By suppressing the V_Ga-related defect within the waveguide layers, reducing the thermal degradation of InGaN-based quantum wells, and controlling the C impurity concentrations within the thick p-type cladding layers, the as-fabricated InGaN-based LDs grown on Si exhibited a significantly reduced threshold current density of 2.25 kA/cm² and an operation voltage of 4.7 V.