RT Journal Article SR Electronic T1 An electrically pumped surface-emitting semiconductor green laser JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP eaav7523 DO 10.1126/sciadv.aav7523 VO 6 IS 1 A1 Ra, Yong-Ho A1 Rashid, Roksana Tonny A1 Liu, Xianhe A1 Sadaf, Sharif Md. A1 Mashooq, Kishwar A1 Mi, Zetian YR 2020 UL http://advances.sciencemag.org/content/6/1/eaav7523.abstract AB 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/cm2, 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.