Two-dimensional GaN: Preparation Based on Liquid Metal Gallium and Photoelectric Properties

doi:10.15541/jim20250210

Abstract

Abstract:

Two-dimensional (2D) gallium nitride (GaN) exhibits broad application prospects in the field of ultraviolet optoelectronics due to its dual characteristics of wide-bandgap semiconductor and quantum confinement effect. However, conventional synthesis methods for 2D GaN, such as metal-organic chemical vapor deposition and molecular beam epitaxy, typically require high growth temperatures, prolonged processing time, and relatively high costs. To address these critical challenges, this work leverages the intrinsic properties of liquid metal gallium, including its low melting point and ease of oxidation to develop an efficient and relatively low-temperature synthesis strategy for 2D GaN. The core of this strategy includes following steps. Firstly, utilizing a straightforward spin-coating exfoliation technique to directly extract an amorphous gallium oxide (Ga₂O₃) from the surface of liquid gallium. Subsequently, subjecting the amorphous Ga₂O₃to a nitridation treatment process at a relatively low temperature of 850 ℃, successfully achieved its conversion into high-crystalline-quality GaN. Characterization results demonstrate that the synthesized 2D GaN possesses a thickness of approximately 2.2 nm, a lateral dimension on the centimeter scale, and a hexagonal wurtzite crystal structure. Furthermore, based on the prepared 2D GaN, a photoconductive ultraviolet photodetector is constructed. Performance characterization results reveal that under a 5 V bias voltage and illumination by 325 nm ultraviolet light, the device exhibits a responsivity of 4.14 A/W and a high detectivity of 1.02×10¹³ Jones. This study demonstrates the successful preparation of large-area 2D GaN material based on liquid gallium metal, providing a valuable reference for the development of low-dimensional and high-performance ultraviolet photodetectors.

Key words: GaN, liquid metal gallium, spin-coating exfoliation method, ultraviolet photodetector

CLC Number:

TQ174

LI Zexi, LU Wenjie, WANG Chao, ZHANG Lu, LI Shuti, GAO Fangliang. Two-dimensional GaN: Preparation Based on Liquid Metal Gallium and Photoelectric Properties[J]. Journal of Inorganic Materials, 2026, 41(3): 377-384.

Figures/Tables 8

Fig. 1 Schematic diagram of two-dimensional GaN preparation

Fig. 2 Morphological characterization of two-dimensional GaN (a) Optical microscope image; (b) SEM image; (c) AFM image with the right figure showing height profile

Fig. 3 Crystal structure characterization of two-dimensional GaN (a) XRD pattern; (b) HRTEM image

Fig. 4 Surface chemical analysis and optical property characterization of two-dimensional GaN (a) High-resolution XPS total spectrum; (b) High-resolution N1s XPS spectrum; (c) High-resolution Ga2p XPS spectrum; (d) Tauc plot corresponding to the absorption spectrum

Fig. 5 Detection performance of two-dimensional GaN photodetector (a) I-V curves in dark and 325 nm light (2.26 mW·cm2); (b) I-V curves of the ultraviolet light with different light intensities in the logarithmic coordinates; (c) I-T curve measured by the ultraviolet light with different light intensities; (d) Light intensity-light current power function diagram

Fig. 6 Photoelectric performance curves of two-dimensional GaN photodetector (a) R; (b) S and R; (c) EQE; (d) LDR and D*

Fig. 7 Response time of detector

Table 1 Performance comparison of GaN-based ultraviolet photodetectors

Material	R/(A·W^-1)	EQE/%	D^*/Jones	Test voltage/V	Ref.
2D	2.01	683	5.34×10¹⁰	10	[29]
Thin film	0.13	49.76	9.79×10⁸	5	[30]
Porous	0.187	62.8	4.34×10¹²	-3	[31]
Nanowires	0.023	−	4.40×10¹¹	0	[32]
Bulk	0.34	−	1.24×10⁹	5	[33]
2D	4.14	1400	1.02×10¹³	5	This work

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