An electrically pumped surface-emitting semiconductor green laser.

Ra, Yong-Ho; Rashid, Roksana Tonny; Liu, Xianhe; Sadaf, Sharif Md; Mashooq, Kishwar; Mi, Zetian · Sci Adv · 2020

basic_science · Level V

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Abstract

Surface-emitting semiconductor lasers have been widely used in data communications, sensing, and recently in Face ID and augmented reality glasses. Here, we report the first achievement of an all-epitaxial, distributed Bragg reflector (DBR)-free electrically injected surface-emitting green laser by exploiting the photonic band edge modes formed in dislocation-free gallium nitride nanocrystal arrays, instead of using conventional DBRs. The device operates at ~523 nm and exhibits a threshold current of ~400 A/cm<sup>2</sup>, which is over one order of magnitude lower compared to previously reported blue laser diodes. Our studies open a new paradigm for developing low-threshold surface-emitting laser diodes from the ultraviolet to the deep visible (~200 to 600 nm), wherein the device performance is no longer limited by the lack of high-quality DBRs, large lattice mismatch, and substrate availability.