We report on the molecular beam epitaxy and characterization of monolayer GaN embedded in N-polar AlN nanowire structures. Deep ultraviolet emission from 4.85 to 5.25 eV is measured by varying the AlN barrier thickness. Detailed optical measurements and direct correlation with first-principles calculations based on density functional and many-body perturbation theory suggest that charge carrier recombination occurs predominantly via excitons in the extremely confined monolayer GaN/AlN heterostructures, with exciton binding energy exceeding 200 meV. We have further demonstrated deep ultraviolet light-emitting diodes (LEDs) with the incorporation of single and double monolayer GaN, which operate at 238 and 270 nm, respectively. These unique deep ultraviolet LEDs exhibit highly stable emission and a small turn-on voltage around 5 V.
Monolayer GaN excitonic deep ultraviolet light emitting diodes
Y. Wu, X. Liu, P. Wang, D. A. Laleyan, K. Sun, Y. Sun, C. Ahn, M. Kira, E. Kioupakis, Z. Mi; Monolayer GaN excitonic deep ultraviolet light emitting diodes. Appl. Phys. Lett. 6 January 2020; 116 (1): 013101. https://doi.org/10.1063/1.5124828
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