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JOURNAL OF SYNTHETIC CRYSTALS ›› 2024, Vol. 53 ›› Issue (4): 676-683.

• Research Articles • Previous Articles     Next Articles

First-Principles Study on Photogalvanic Effect and Strain Engineering of Monolayer SnS

XU Zhonghui1,2, XU Shengyuan1, LIU Chuanchuan1, LIU Guogang3   

  1. 1. School of Information Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China;
    2. Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Shanghai 200092, China;
    3. MOE Key Laboratory of Microstructured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
  • Received:2023-12-04 Online:2024-04-15 Published:2024-04-19

Abstract: Photodetectors are widely used in various fields, such as industrial manufacturing and military defense. Researchers have recently sought a photodetector that combines high polarization sensitivity and a robust optical response. As an anisotropic semiconductor material, SnS holds potential for photodetection across the visible light spectrum. This study employs first-principles density functional theory (DFT) along with the non-equilibrium Green's function (NEGF) method to theoretically investigate the optoelectronic properties of the SnS monolayer in two device orientations: Armchair and Zigzag. It is found that the maximum photocurrent values between the two orientations are small at zero bias voltage, and stable photocurrent can be obtained by adding bias voltage. We examine the maximum photocurrent variation under linearly polarized light irradiation within a small bias voltage range (0.1 to 1.0 V), found for the maximum photoresponse of monolayer SnS to be large and stable at photon energy of 2.4 and 3.2 eV, and analyze the underlying mechanism of photoresponse, employing energy band and density of state diagrams. Additionally, we have calculated the extinction ratio of the SnS monolayer, confirming its strong polarization sensitivity. Finally, by subjecting the device to biaxial strain, we significantly speculate to enhance its asymmetry, leading to a substantial increase in photocurrent at zero bias. A compressive strain of -6% notably increases the photocurrent. These findings offer valuable theoretical insights for the design of SnS monolayers as photodetectors.

Key words: monolayer SnS, photodetector, first-principle, maximum photoresponse, polarization sensitivity, strain engineering

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