Advancing prospects in ultrawide bandgap semiconductor materials

Ultrawide bandgap (UWBG) semiconductors represent an expanding frontier in power electronic components. They enable greater speed and efficiency for high-power electronics, radio-frequency and microwave electronics, deep-ultraviolet optoelectronics, and extreme environmental applications — all in a package smaller than their silicon- or gallium arsenide-based counterparts.

At the forefront of this growing field, boron-carbon-nitrogen (B-C-N) compounds with adjustable electronic structures and semiconductor properties are uniquely suited to optics, catalysis, data storage, and many other areas. But the lack of homogeneity in such crystallized compounds has limited their potential as UWBG semiconductors.

Xu et al. used ball milling and high-pressure high-temperature (HPHT) techniques to synthesize B-C-N compound bulk materials from graphite (C) and hexagonal boron nitride (h-BN) powders. The synthesized compounds become highly crystalline layered materials with tunable optical and electrical properties.

“This is due to intercalating graphene layers between C-doped h-BN layers to form B-C-N layered materials under HPHT conditions,” said author Zhanhui Ding. “We found that the carbon atoms occupy boron sites and nitrogen sites of the h-BN layers in an unbalanced way, leading to the n-type conductivity of the B-C-N layered materials.”

By varying the carbon content, the authors were able to produce n-type B-C-N semiconductors with bandgaps that can be adjusted from 3.4 eV to 6.0 eV. Their results show how to achieve bandgap regulation of B-C-N compounds, which is a promising development in realizing the enormous potential of these compounds as UWBG semiconductor materials.

“The carrier mobility of B-C-N semiconductors is much lower than reported for graphene,” Ding said. “This issue is worth exploring in the future.”

Source: “Ternary B-C-N compounds layered materials with regulated electronic properties and ultrawide bandgaps,” by Baoyin Xu, Haozhe Du, Bin Yang, Zhanhui Ding, Xiancheng Wang, Yanchao Wang, Ziheng Li, Yongfeng Li, Bin Yao, Hong-an Ma, and Yucheng Lan, Applied Physics Letters (2023). The article can be accessed at http://doi.org/10.1063/5.0139755 .