Yellow-Green Luminescence Due to Polarity-Dependent Incorporation of Carbon Impurities in Self-Assembled GaN Microdisk

Zhiwei Si; Zongliang Liu; Yaoqiao Hu; Xiaoxuan Wang; Chunxiang Xu; Shunan Zheng; Xiaoming Dong; Xiaodong Gao; Jingjing Chen; Jianfeng Wang; Ke Xu

doi:10.1021/acs.nanolett.2c03274

Yellow-Green Luminescence Due to Polarity-Dependent Incorporation of Carbon Impurities in Self-Assembled GaN Microdisk

Nano Lett. 2022 Nov 9;22(21):8670-8678. doi: 10.1021/acs.nanolett.2c03274. Epub 2022 Oct 18.

Authors

Zhiwei Si^{1

2

3}, Zongliang Liu^{1

3}, Yaoqiao Hu⁴, Xiaoxuan Wang⁵, Chunxiang Xu⁵, Shunan Zheng¹, Xiaoming Dong¹, Xiaodong Gao¹, Jingjing Chen¹, Jianfeng Wang^{1

2

6

3}, Ke Xu^{1

2

6

3}

Affiliations

¹ Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, Jiangsu, China.
² School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, Anhui, China.
³ Shenyang National Laboratory for Materials Science, Jiangsu Institute of Advanced Semiconductors, NW-20, Nanopolis Suzhou, 99 Jinji Lake Avenue, Suzhou Industrial Park, Suzhou 215123, Jiangsu, China.
⁴ Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States.
⁵ State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
⁶ Suzhou Nanowin Science and Technology Co, Ltd., Suzhou 215123, Jiangsu, China.

PMID: 36256439
DOI: 10.1021/acs.nanolett.2c03274

Abstract

Yellow-green luminescence (YGL) competes with near-bandgap emission (NBE) for carrier recombination channels, thereby reducing device efficiency; yet uncovering the origin of YGL remains a major challenge. In this paper, nearly stress-free and low dislocation density self-assembled GaN microdisks were synthesized by Na-flux method. The YGL of GaN microdisks highly depend on their polar facets. Variable accelerating voltage/power CL, variable temperature PL, and Raman spectroscopy are further performed to clarify the origin of polarity dependence of GaN microdisk YGL behavior, which indicates its independence of dislocations, surface effects, stress, crystalline quality, and gallium vacancies. It was found that the incorporation ability of carbon impurities in the polar (0001) facet is greater than that in the semipolar (101̅1) facets, producing higher content of C_N or C_NO_N defects, resulting in a more pronounced YGL in the polar (0001) facet of GaN.

Keywords: CN or CNON deep-level defects; DFT calculation; GaN microdisk; Na flux; Yellow-green luminescence.