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Zhong M, Meng H, Liu S, Yang H, Shen W, Hu C, Yang J, Ren Z, Li B, Liu Y, He J, Xia Q, Li J, Wei Z. In-Plane Optical and Electrical Anisotropy of 2D Black Arsenic. ACS NANO 2021; 15:1701-1709. [PMID: 33331154 DOI: 10.1021/acsnano.0c09357] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Low-symmetry two-dimensional (2D) semiconductors have attracted great attention because of their rich in-plane anisotropic optical, electrical, and thermoelectric properties and potential applications in multifunctional nanoelectronic and optoelectronic devices. However, anisotropic 2D semiconductors with high performance are still very limited. Here, we report the systematic study of in-plane anisotropic properties in few-layered b-As that is a narrow-gap semiconductor, based on the experimental and theoretical investigations. According to experimental results, we have come up with a simple method for identifying the orientation of b-As crystals. Meanwhile, we show that the maximum mobility of electrons and holes was measured in the in-plane armchair (AC) direction. The measured maximum electron mobility ratio is about 2.68, and the hole mobility ratio is about 1.79.
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Affiliation(s)
- Mianzeng Zhong
- Hunan Key Laboratory of Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, Hunan, China
| | - Haotong Meng
- Hunan Key Laboratory of Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, Hunan, China
| | - Sijie Liu
- Hunan Key Laboratory of Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, Hunan, China
| | - Huai Yang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
| | - Wanfu Shen
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Chunguang Hu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Juehan Yang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
| | - Zhihui Ren
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
| | - Bo Li
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, Hunan, China
| | - Yunyan Liu
- School of Physics and Optoelectronic Engineering, Shandong University of Technology, Zibo 255049, Shandong, China
| | - Jun He
- Hunan Key Laboratory of Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, Hunan, China
| | - Qinglin Xia
- Hunan Key Laboratory of Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, Hunan, China
| | - Jingbo Li
- Institute of Semiconductors, South China Normal University, Guangzhou 510631, China
| | - Zhongming Wei
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
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Shen W, Hu C, Tao J, Liu J, Fan S, Wei Y, An C, Chen J, Wu S, Li Y, Liu J, Zhang D, Sun L, Hu X. Resolving the optical anisotropy of low-symmetry 2D materials. NANOSCALE 2018; 10:8329-8337. [PMID: 29687795 DOI: 10.1039/c7nr09173g] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Optical anisotropy is one of the most fundamental physical characteristics of emerging low-symmetry two-dimensional (2D) materials. It provides abundant structural information and is crucial for creating diverse nanoscale devices. Here, we have proposed an azimuth-resolved microscopic approach to directly resolve the normalized optical difference along two orthogonal directions at normal incidence. The differential principle ensures that the approach is only sensitive to anisotropic samples and immune to isotropic materials. We studied the optical anisotropy of bare and encapsulated black phosphorus (BP) and unveiled the interference effect on optical anisotropy, which is critical for practical applications in optical and optoelectronic devices. A multi-phase model based on the scattering matrix method was developed to account for the interference effect and then the crystallographic directions were unambiguously determined. Our result also suggests that the optical anisotropy is a probe to measure the thickness with monolayer resolution. Furthermore, the optical anisotropy of rhenium disulfide (ReS2), another class of anisotropic 2D materials, with a 1T distorted crystal structure, was investigated, which demonstrates that our approach is suitable for other anisotropic 2D materials. This technique is ideal for optical anisotropy characterization and will inspire future efforts in BP and related anisotropic 2D nanomaterials for engineering new conceptual nanodevices.
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Affiliation(s)
- Wanfu Shen
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, No. 92 Weijin Road, CN-300072 Tianjin, China.
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Hu C, Huo S, Shen W, Li Y, Hu X. Reflectance difference microscopy for nanometre thickness microstructure measurements. J Microsc 2018; 270:318-325. [PMID: 29383705 DOI: 10.1111/jmi.12685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 12/21/2017] [Accepted: 01/10/2018] [Indexed: 11/27/2022]
Abstract
The discontinuity of medium at the boundary produces optically anisotropic response which makes reflectance difference microscopy (RDM) a potential method for nanometre-thickness microstructure measurements. Here, we present the methodology of RDM for the edge measurement of ultrathin microstructure. The RD signal of microstructure's boundary is mathematically deduced according to boundary condition and polarization optics theory. A normal-incidence RDM setup was built simply with one linear polarizer, one liquid crystal variable retarder and one 5 × objective. Then, the performance of the developed setup was identified using homogenous reflection mirror and high quality linear polarizer. For demonstration, microstructures array with 100 nm step height was measured. The results show that the RD signal is sensitive to the edge and its sign reflects the change direction of the edge. Furthermore, a height sensitivity of better than 10 nm and a spatial resolution of ∼3 μm offer this technique a good candidate for characterizing ultrathin microstructures.
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Affiliation(s)
- C Hu
- State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, China
| | - S Huo
- State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, China.,College of Mechanical Engineering, Chengdu Technological University, Chengdu, Sichuan Province, China
| | - W Shen
- State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, China
| | - Y Li
- State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, China
| | - X Hu
- State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, China
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