title: Controlled Synthesis of High-Mobility Atomically Thin Bismuth Oxyselenide Crystals.
abstract: Non-neutral layered crystals, another group of two-dimensional (2D) materials that lack a well-defined van der Waals (vdWs) gap, are those that form strong chemical bonds in-plane but display weak out-of-plane electrostatic interactions, exhibiting intriguing properties for the bulk counterpart. However, investigation of the properties of their atomically thin counterpart are very rare presumably due to the absence of efficient ways to achieve large-area high-quality 2D crystals. Here, high-mobility atomically thin Bi2O2Se, a typical non-neutral layered crystal without a standard vdWs gap, was synthesized via a facial chemical vapor deposition (CVD) method, showing excellent controllability for thickness, domain size, nucleation site, and crystal-phase evolution. Atomically thin, large single crystals of Bi2O2Se with lateral size up to ∼200 μm and thickness down to a bilayer were obtained. Moreover, optical and electrical properties of the CVD-grown 2D Bi2O2Se crystals were investigated, displaying a size-tunable band gap upon thinning and an ultrahigh Hall mobility of >20000 cm2V-1s-1at 2 K. Our results on the high-mobility 2D Bi2O2Se semiconductor may activate the synthesis and related fundamental research of other non-neutral 2D materials.
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Jinxiong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.|Academy for Advanced Interdisciplinary Studies, Peking University , Beijing 100871, P. R. China.
authors.forename: Congwei
authors.initials: C
authors.lastname: Tan
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.|Academy for Advanced Interdisciplinary Studies, Peking University , Beijing 100871, P. R. China.
authors.forename: Zhenjun
authors.initials: Z
authors.lastname: Tan
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Jianbo
authors.identifier: 0000-0001-6610-3916
authors.initials: J
authors.lastname: Yin
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Dang
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Mingzhan
authors.initials: M
authors.lastname: Wang
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.|Academy for Advanced Interdisciplinary Studies, Peking University , Beijing 100871, P. R. China.
authors.forename: Hailin
authors.identifier: 0000-0003-1569-0238
authors.initials: H
authors.lastname: Peng
keywords: Two-dimensional materials; bismuth oxyselenide; chemical vapor deposition; controlled synthesis; high mobility; non-neutral layered semiconductor