Low Residual Carrier Concentration and High Mobility in 2D Semiconducting Bi2O2Se

• Published in: Nano letters 2019-01, Vol.19 (1), p.197-202
• Main Authors: Wu, Jinxiong, Qiu, Chenguang, Fu, Huixia, Chen, Shulin, Zhang, Congcong, Dou, Zhipeng, Tan, Congwei, Tu, Teng, Li, Tianran, Zhang, Yichi, Zhang, Zhiyong, Peng, Lian-Mao, Gao, Peng, Yan, Binghai, Peng, Hailin
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.8b03696

The air-stable and high-mobility two-dimensional (2D) Bi2O2Se semiconductor has emerged as a promising alternative that is complementary to graphene, MoS2, and black phosphorus for next-generation digital applications. However, the room-temperature residual charge carrier concentration of 2D Bi2O2Se nanoplates synthesized so far is as high as about 1019–1020 cm–3, which results in a poor electrostatic gate control and unsuitable threshold voltage, detrimental to the fabrication of high-performance low-power devices. Here, we first present a facile approach for synthesizing 2D Bi2O2Se single crystals with ultralow carrier concentration of ∼1016 cm–3 and high Hall mobility up to 410 cm2 V–1 s–1 simultaneously at room temperature. With optimized conditions, these high-mobility and low-carrier-concentration 2D Bi2O2Se nanoplates with domain sizes greater than 250 μm and thicknesses down to 4 layers (∼2.5 nm) were readily grown by using Se and Bi2O3 powders as coevaporation sources in a dual heating zone chemical vapor deposition (CVD) system. High-quality 2D Bi2O2Se crystals were fabricated into high-performance and low-power transistors, showing excellent current modulation of >106, robust current saturation, and low threshold voltage of −0.4 V. All these features suggest 2D Bi2O2Se as an alternative option for high-performance low-power digital applications.