2D janus niobium oxydihalide NbOXY: Multifunctional piezoelectric semiconductor for electronics, photonics, sensing and sustainable energy applications

• DOI: 10.1016/j.mtphys.2023.101001
• Publication Date: 2023-02-02T03:14:38Z
• Authors: Tong Su; Ching Hua Lee; San-Dong Guo; Guangzhao Wang; Wee-Liat Ong; Liemao Cao; Weiwei Zhao; Shengyuan A. Yang; Yee Sin Ang
• Keywords: 02 engineering and technology; 0210 nano-technology

Two-dimensional (2D) niobium oxydihalide NbOI2 has been recently demonstrated as an excellent in-plane piezoelectric and nonlinear optical material. Here we show that Janus oxydihalide, NbOXY (X, Y = Cl, Br, I X ≠ Y), is a multifunctional anisotropic semiconductor family with exceptional piezoelectric, electronic, photocatalytic properties. are stable flexible monolayers band gap around the visible light regime of ∼1.9 eV. The carrier mobility exhibits exceptionally strong anisotoropy ratio ∼400, which larger than most 2D semiconductors. large deformation potential NbOXYmonolayers leads to piezoresistive effect useful for strain sensing application. Inversion symmetry breaking in generates sizable out-of-plane d31 response while still retaining piezoelectricity. Remarkably, additional response, d32 0.55 pm/V. G0W0-BSE calculation further reveals linear dichroism visible-to-ultraviolet regime. absorption peaks 14 ∼ 18% deep UV (5 6 eV) outperform vast majority other materials. high mobility, absorption, built-in electric field alignment compatible overall water splitting suggest strengths solar-to-hydrogen conversion. We propose directional stress device demonstrate how piezoelectricity can be harnessed functional applications. Our findings unveil electronics, optoelectronics, photonics, piezoelectronics sustainable energy