中国物理B ›› 2020, Vol. 29 ›› Issue (1): 17802-017802.doi: 10.1088/1674-1056/ab5a3a

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Thickness-dependent excitonic properties of atomically thin 2H-MoTe2

Jin-Huan Li(李金焕), Dan Bing(邴单), Zhang-Ting Wu(吴章婷), Guo-Qing Wu(吴国庆), Jing Bai(白静), Ru-Xia Du(杜如霞), Zheng-Qing Qi(祁正青)   

  1. 1 Department of Basic Teaching, Nanjing Tech University Pujiang Institute, Nanjing 211134, China;
    2 School of Network and Communication Engineering, Jinling Institute of Technology, Nanjing 211169, China;
    3 Lab for Nanoelectronics and NanoDevices, Department of Electronics Science and Technology, Hangzhou Dianzi University, Hangzhou 310018, China
  • 收稿日期:2019-10-20 修回日期:2019-11-19 出版日期:2020-01-05 发布日期:2020-01-05
  • 通讯作者: Zheng-Qing Qi E-mail:qi.zq@163.com
  • 基金资助:
    Project supported by the Natural Science Research Projects in Colleges and Universities of Jiangsu Province, China (Grant No. 18KJD140003).

Thickness-dependent excitonic properties of atomically thin 2H-MoTe2

Jin-Huan Li(李金焕)1, Dan Bing(邴单)1, Zhang-Ting Wu(吴章婷)3, Guo-Qing Wu(吴国庆)1, Jing Bai(白静)1, Ru-Xia Du(杜如霞)1, Zheng-Qing Qi(祁正青)2   

  1. 1 Department of Basic Teaching, Nanjing Tech University Pujiang Institute, Nanjing 211134, China;
    2 School of Network and Communication Engineering, Jinling Institute of Technology, Nanjing 211169, China;
    3 Lab for Nanoelectronics and NanoDevices, Department of Electronics Science and Technology, Hangzhou Dianzi University, Hangzhou 310018, China
  • Received:2019-10-20 Revised:2019-11-19 Online:2020-01-05 Published:2020-01-05
  • Contact: Zheng-Qing Qi E-mail:qi.zq@163.com
  • Supported by:
    Project supported by the Natural Science Research Projects in Colleges and Universities of Jiangsu Province, China (Grant No. 18KJD140003).

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摘要： Two-dimensional (2D) 2H-MoTe2 is a promising semiconductor because of its small bandgap, strong absorption, and low thermal conductivity. In this paper, we systematically study the optical and excitonic properties of atomically thin 2H-MoTe2 (1-5 layers). Due to the fact that the optical contrast and Raman spectra of 2H-MoTe2 with different thicknesses exhibit distinctly different behaviors, we establish a quantitative method by using optical images and Raman spectra to directly identify the layers of 2H-MoTe2 thin films. Besides, excitonic states and binding energy in monolayer/bilayer 2H-MoTe2 are measured by temperature-dependent photoluminescence (PL) spectroscopy. At temperature T=3.3 K, we can observe an exciton emission at ~1.19 eV and trion emission at ~1.16 eV for monolayer 2H-MoTe2. While at room temperature, the exciton emission and trion emission both disappear for their small binding energy. We determine the exciton binding energy to be 185 meV (179 meV), trion binding energy to be 20 meV (18 meV) for the monolayer (bilayer) 2H-MoTe2. The thoroughly studies of the excitonic states in atomically thin 2H-MoTe2 will provide guidance for future practical applications.

关键词: 2H-MoTe2, photoluminescence, Raman, exciton and trion

Abstract: Two-dimensional (2D) 2H-MoTe2 is a promising semiconductor because of its small bandgap, strong absorption, and low thermal conductivity. In this paper, we systematically study the optical and excitonic properties of atomically thin 2H-MoTe2 (1-5 layers). Due to the fact that the optical contrast and Raman spectra of 2H-MoTe2 with different thicknesses exhibit distinctly different behaviors, we establish a quantitative method by using optical images and Raman spectra to directly identify the layers of 2H-MoTe2 thin films. Besides, excitonic states and binding energy in monolayer/bilayer 2H-MoTe2 are measured by temperature-dependent photoluminescence (PL) spectroscopy. At temperature T=3.3 K, we can observe an exciton emission at ~1.19 eV and trion emission at ~1.16 eV for monolayer 2H-MoTe2. While at room temperature, the exciton emission and trion emission both disappear for their small binding energy. We determine the exciton binding energy to be 185 meV (179 meV), trion binding energy to be 20 meV (18 meV) for the monolayer (bilayer) 2H-MoTe2. The thoroughly studies of the excitonic states in atomically thin 2H-MoTe2 will provide guidance for future practical applications.

Key words: 2H-MoTe2, photoluminescence, Raman, exciton and trion

中图分类号:  (Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures)

  • 78.67.-n
78.55.-m (Photoluminescence, properties and materials) 74.25.nd (Raman and optical spectroscopy)