Nanoscale phase separation on an AlGaN surface characterized by scanning diffusion microscopy

doi:10.1364/OE.487405

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	Nanoscale phase separation on an AlGaN surface characterized by scanning diffusion microscopy
	B. Liu; Z. Liu; G. Xu; W. Song; C. Zhang; K. Chen; S. Han; X. Sun; D. Li and K. Xu
	2023
发表期刊	Optics Express
ISSN	10944087
卷号	31 期号:9 页码:14945-14953
摘要	AlGaN is an important material for deep ultraviolet optoelectronic devices and electronic devices. The phase separation on the AlGaN surface means small-scale compositional fluctuations of Al, which is prone to degrade the performance of devices. In order to study the mechanism of the surface phase separation, the Al0.3Ga0.7N wafer was investigated by the scanning diffusion microscopy method based on the photo-assisted Kelvin force probe microscope. The response of the surface photovoltage near the bandgap was quite different for the edge and the center of the island on the AlGaN surface. We utilize the theoretical model of scanning diffusion microscopy to fit the local absorption coefficients from the measured surface photovoltage spectrum. During the fitting process, we introduce as and ab parameters (bandgap shift and broadening) to describe the local variation of absorption coefficients α(as, ab, λ). The local bandgap and Al composition can be calculated quantitatively from the absorption coefficients. The results show that there is lower bandgap (about 305 nm) and lower Al composition (about 0.31) at the edge of the island, compared with those at the center of the island (about 300 nm for bandgap and 0.34 for Al composition). Similar to the edge of the island, there is a lower bandgap at the V-pit defect which is about 306 nm corresponding to the Al composition of about 0.30. These results mean Ga enrichment both at the edge of the island and the V-pit defect position. It proves that scanning diffusion microscopy is an effective method to review the micro-mechanism of AlGaN phase separation. © 2023 Optica Publishing Group.
DOI	10.1364/OE.487405
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收录类别	sci ; ei
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文献类型	期刊论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/67682
专题	中国科学院长春光学精密机械与物理研究所
推荐引用方式 GB/T 7714	B. Liu,Z. Liu,G. Xu,et al. Nanoscale phase separation on an AlGaN surface characterized by scanning diffusion microscopy[J]. Optics Express,2023,31(9):14945-14953.
APA	B. Liu.,Z. Liu.,G. Xu.,W. Song.,C. Zhang.,...&D. Li and K. Xu.(2023).Nanoscale phase separation on an AlGaN surface characterized by scanning diffusion microscopy.Optics Express,31(9),14945-14953.
MLA	B. Liu,et al."Nanoscale phase separation on an AlGaN surface characterized by scanning diffusion microscopy".Optics Express 31.9(2023):14945-14953.

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