Water-Induced Bandgap Engineering in Nanoribbons of Hexagonal Boron Nitride

Chen Chen; Yang Hang; Hui Shan Wang; Yang Wang; Xiujun Wang; Chengxin Jiang; Yu Feng; Chenxi Liu; Eli Janzen; James H Edgar; Zhipeng Wei; Wanlin Guo; Weida Hu; Zhuhua Zhang; Haomin Wang; Xiaoming Xie

doi:10.1002/adma.202303198

Water-Induced Bandgap Engineering in Nanoribbons of Hexagonal Boron Nitride

Adv Mater. 2023 Sep;35(36):e2303198. doi: 10.1002/adma.202303198. Epub 2023 Jul 12.

Authors

Chen Chen^{1

2

3}, Yang Hang⁴, Hui Shan Wang^{1

2

3}, Yang Wang⁵, Xiujun Wang^{1

2

3}, Chengxin Jiang^{1

6}, Yu Feng^{1

2

3}, Chenxi Liu^{1

2

3}, Eli Janzen⁷, James H Edgar⁷, Zhipeng Wei⁸, Wanlin Guo⁴, Weida Hu⁵, Zhuhua Zhang⁴, Haomin Wang^{1

2

3}, Xiaoming Xie^{1

6}

Affiliations

¹ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
² National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China.
³ CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai, 200050, China.
⁴ Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
⁵ State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China.
⁶ School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
⁷ Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA.
⁸ State Key Laboratory of High Power Semiconductor Lasers, Changchun University of Science and Technology, Changchun, 130022, China.

PMID: 37400106
DOI: 10.1002/adma.202303198

Abstract

Different from hexagonal boron nitride (hBN) sheets, the bandgap of hBN nanoribbons (BNNRs) can be changed by spatial/electrostatic confinement. It is predicted that a transverse electric field can narrow the bandgap and even cause an insulator-metal transition in BNNRs. However, experimentally introducing an overhigh electric field across the BNNR remains challenging. Here, it is theoretically and experimentally demonstrated that water adsorption greatly reduces the bandgap of zigzag-oriented BNNRs (zBNNRs). Ab initio calculations show that water molecules can be favorably assembled within the trench between two adjacent BNNRs to form a polar ice layer, which induces a transverse equivalent electric field of over 2 V nm^-1 accounting for the bandgap reduction. Field-effect transistors are successfully fabricated from zBNNRs with different widths. The conductance of water-adsorbed zBNNRs can be tuned over 3 orders in magnitude via modulation of the equivalent electrical field at room temperature. Furthermore, photocurrent response measurements are taken to determine the optical bandgaps of zBNNRs with water adsorption. The zBNNR with increased width can exhibit a bandgap down to 1.17 eV. This study offers fundamental insights into new routes toward realizing electronic/optoelectronic devices and circuits based on hexagonal boron nitride.

Keywords: bandgap engineering; boron nitride nanoribbons; edge modification; hexagonal boron nitride; transverse potential; water adsorption.

Abstract

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