Semiconductor Performance Optimization on Quasi-Two-Dimensional Bi2O2(SxSe1- x) through Monotonous Alloying

Yong-Jyun Wang; Li-Lun Chu; Yu-Hao Tu; Li-Hui Tsao; Ming-Kuan Fan; Wei-Ting Chen; Chien-Wei Chen; Chan-Yuen Chang; Yuan-Chih Chang; Yu-Lun Chueh; Po-Wen Chiu; Chao-Hui Yeh; Ying-Hao Chu

doi:10.1021/acs.nanolett.5c01164

Semiconductor Performance Optimization on Quasi-Two-Dimensional Bi₂O₂(S_xSe_{1- x}) through Monotonous Alloying

Nano Lett. 2025 May 21;25(20):8186-8193. doi: 10.1021/acs.nanolett.5c01164. Epub 2025 May 9.

Authors

Yong-Jyun Wang¹, Li-Lun Chu¹, Yu-Hao Tu¹, Li-Hui Tsao¹, Ming-Kuan Fan¹, Wei-Ting Chen², Chien-Wei Chen³, Chan-Yuen Chang³, Yuan-Chih Chang^{4

5}, Yu-Lun Chueh^{1

6

7}, Po-Wen Chiu⁴, Chao-Hui Yeh^{2

4

5}, Ying-Hao Chu^{1

2}

Affiliations

¹ Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300044, Taiwan.
² College of Semiconductor Research, National Tsing Hua University, Hsinchu 300044, Taiwan.
³ Taiwan Instrument Research Institute, National Applied Research Laboratories, Hsinchu 300092, Taiwan.
⁴ Department of Electrical Engineering, National Tsing Hua University, Hsinchu 300044, Taiwan.
⁵ Institute of Electronics Engineering, National Tsing Hua University, Hsinchu 300044, Taiwan.
⁶ Department of Physics, National Sun Yat-Sen University, Kaohsiung 804201, Taiwan.
⁷ Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.

Abstract

Bismuth oxychalcogenides (Bi₂O₂X, where X = S, Se, Te) have garnered significant attention recently due to their high electron mobility, air stability, and excellent photoelectric properties. Therefore, precise control and optimization over the properties of these novel quasi-2D materials are crucial for practical applications. In this study, we synthesize epitaxial films of Bi₂O₂(S,Se) by the monotonous alloying of sulfur (S) and selenium (Se). Our findings reveal that the lattice constants, band gaps, and electrical properties of the films vary according to the elemental composition. Further, we observed an enhanced field-effect mobility of ∼215 cm²/(V s) and an on/off ratio of ∼10⁶ in the Bi₂O₂(S_0.4Se_0.6) heterostructures with a Bi₂SeO₅ (BSO) oxide layer. With these efforts, this work establishes a pathway toward developing novel designs for 2D Bi₂O₂X materials.

Keywords: 2D alloy; Bi2O2S; Bi2O2Se; semiconductor device.