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

Abstract

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.

Surface electronic structure of bismuth oxychalcogenides

“…The strong spin-orbit interaction in Bi 2 O 2 Se nanoplates has also been confirmed through magnetotransport measurements [55]. The creation on the basis of these Bi 2 O 2 Se nanolayers of a highperformance and low-power transistor [58], supersensitive 2D phototransistors [59], the top-gate field-effect transistor [53], and a high-performing infrared photodetector [60] and the possibility of integrating high-quality Bi 2 O 2 Se with the silicon complementary metal-oxide-semiconductor technologies [59] have also been reported.…”

2D Metal Chalcogenides for IR Photodetection

“…Very lately, a new star ternary material Bi 2 O 2 Se joins into the 2D family . Bi 2 O 2 Se possesses high Hall mobility (29 000 cm 2 V −1 s −1 at 1.9 K and 450 cm 2 V −1 s −1 at room temperature) and appropriate bandgap of 0.8 eV, which pave the way for high sensitivity and fast response IR photodetection.…”

Exploitation of Bi2O2Se/graphene van der Waals heterojunction for creating efficient photodetectors and short‐channel field‐effect transistors

“…Particularly, graphene shows dangling‐free bonds and is widely utilized to form vdW heterojunctions with the other two‐dimensional (2D) materials such as molybdenum sulfide . Recently, a 2D Bi 2 O 2 Se crystal, tetragonal (Bi 2 O 2 ) n layers alternately stacked with Se n layers along the c ‐axis, is synthesized by chemical vapor deposition (CVD) . The 2D Bi 2 O 2 Se is an air‐stable semiconductor (band gap of 0.8 eV) with high mobility and observed with quantum oscillations .…”

“…The 2D Bi 2 O 2 Se is an air‐stable semiconductor (band gap of 0.8 eV) with high mobility and observed with quantum oscillations . In the applications of photodetector, the 2D Bi 2 O 2 Se is of ultrafast response time, and in the case of field‐effect transistors (FETs), it shows a low residual carrier concentration . It is expected to stack graphene and the Bi 2 O 2 Se to form vdW heterojunctions, by which the advanced features of the optoelectronic and electronic device are highly achievable.…”

“…7 Recently, a 2D Bi 2 O 2 Se crystal, tetragonal (Bi 2 O 2 ) n layers alternately stacked with Se n layers along the c-axis, is synthesized by chemical vapor deposition (CVD). [11][12][13] The 2D Bi 2 O 2 Se is an air-stable semiconductor (band gap of 0.8 eV) with high mobility and observed with quantum oscillations. 11 In the applications of photodetector, the 2D Bi 2 O 2 Se is of ultrafast response time, and in the case of field-effect transistors (FETs), it shows a low residual carrier concentration.…”