Open Access

ARTICLE

Molecular Beam Epitaxial Growth and Device Characterization of AlGaN Nanowire Ultraviolet-B Light-Emitting Diodes

M. Rajan Philip¹, T. H. Q. Bui¹, D. D. Choudhary¹, M. Djavid¹, P. Vu, T. T. Pham², H.-D. Nguyen³, H. P. T Nguyen^2,4*

1 Department of Electrical and Computer Engineering, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, New Jersey, 07102, United States.
2 Faculty of Applied Sciences, Ho Chi Minh University of Technology, Vietnam National University in Ho Chi Minh City, 268 Ly Thuong Kiet, Ward 14, District 10, Ho Chi Minh City, 70001, Vietnam.
3 Vietnam Academy of Science and Technology, Institute of Applied Materials Science, 1 Mac Dinh Chi Street, District 1, Ho Chi Minh City, 70001, Vietnam.
⁴ Electronic Imaging Center, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, New Jersey, 07102, United States.
* Corresponding Author: Hieu P. T. Nguyen. hieu.p.nguyen@njit.edu; Phone: +1-973-596-3523.

Journal of Advanced Optics and Photonics 2018, 1(1), 3-11. https://doi.org/10.32604/jaop.2018.001.003

Abstract

We report on the design and fabrication of high performance AlxGa1−xN nanowire ultraviolet (UV) light-emitting diodes (LEDs) on silicon substrate by molecular beam epitaxy. The emission wavelength and surface morphology of nanowires can be controlled by varying the growth parameters that include substrate temperatures and/or Aluminum/Gallium flux ratios. The devices exhibit excellent current-voltage characteristics with relatively low resistance. Such nanowire LEDs generate strong emission in the UV-B band tuning from 290 nm to 330 nm. The electroluminescence spectra show virtually invariant blue-shift under injection current from 50 mA to 400 mA, suggesting the presence of a negligible quantum-confined Stark effect. Moreover, we have shown that, the AlGaN nanowire LEDs using periodic structures, can achieve high light extraction efficiency of ~ 89% and 92% for emissions at 290nm and 320nm, respectively. The randomly arranged nanowire 290 nm UV LEDs exhibit light extraction efficiency of ~ 56% which is higher compared to current AlGaN based thin-film UV LEDs.

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