中国物理B ›› 2018, Vol. 27 ›› Issue (7): 77301-077301.doi: 10.1088/1674-1056/27/7/077301

• SPECIAL TOPIC—Recent advances in thermoelectric materials and devices • 上一篇    下一篇

Image charge effect on the light emission of rutile TiO2(110) induced by a scanning tunneling microscope

Chaoyu Guo(郭钞宇), Xiangzhi Meng(孟祥志), Qin Wang(王钦), Ying Jiang(江颖)   

  1. 1 International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China;
    2 Collaborative Innovation Center of Quantum Matter, Beijing 100871, China;
    3 CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2018-05-25 出版日期:2018-07-05 发布日期:2018-07-05
  • 通讯作者: Ying Jiang E-mail:yjiang@pku.edu.cn
  • 基金资助:

    Project supported by the National Key R&D Program of China (Grant Nos. 2016YFA0300901 and 2017YFA0205003), the National Natural Science Foundation of China (Grant Nos. 11634001 and 21725302), and the Key Research Program of the Chinese Academy of Sciences (Grant No. XDPB08-1).

Image charge effect on the light emission of rutile TiO2(110) induced by a scanning tunneling microscope

Chaoyu Guo(郭钞宇)1, Xiangzhi Meng(孟祥志)1, Qin Wang(王钦)1, Ying Jiang(江颖)1,2,3   

  1. 1 International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China;
    2 Collaborative Innovation Center of Quantum Matter, Beijing 100871, China;
    3 CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-05-25 Online:2018-07-05 Published:2018-07-05
  • Contact: Ying Jiang E-mail:yjiang@pku.edu.cn
  • Supported by:

    Project supported by the National Key R&D Program of China (Grant Nos. 2016YFA0300901 and 2017YFA0205003), the National Natural Science Foundation of China (Grant Nos. 11634001 and 21725302), and the Key Research Program of the Chinese Academy of Sciences (Grant No. XDPB08-1).

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摘要：

The plasmon-enhanced light emission of rutile TiO2(110) surface has been investigated by a low-temperature scanning tunneling microscope (STM). We found that the photon emission arises from the inelastic electron tunneling between the STM tip and the conduction band or defect states of TiO2(110). In contrast to the Au(111) surface, the maximum photon energy as a function of the bias voltage clearly deviates from the linear scaling behavior, suggesting the non-negligible effect of the STM tip on the band structure of TiO2. By performing differential conductance (dI/dV) measurements, it was revealed that such a deviation is not related to the tip-induced band bending, but is attributed to the image charge effect of the metal tip, which significantly shifts the band edges of the TiO2(110) towards the Femi level (EF) during the tunneling process. This work not only sheds new lights onto the understanding of plasmon-enhanced light emission of semiconductor surfaces, but also opens up a new avenue for engineering the plasmon-mediated interfacial charge transfer in molecular and semiconducting materials.

关键词: scanning tunneling microscopy, light emission, TiO2, plasmon

Abstract:

The plasmon-enhanced light emission of rutile TiO2(110) surface has been investigated by a low-temperature scanning tunneling microscope (STM). We found that the photon emission arises from the inelastic electron tunneling between the STM tip and the conduction band or defect states of TiO2(110). In contrast to the Au(111) surface, the maximum photon energy as a function of the bias voltage clearly deviates from the linear scaling behavior, suggesting the non-negligible effect of the STM tip on the band structure of TiO2. By performing differential conductance (dI/dV) measurements, it was revealed that such a deviation is not related to the tip-induced band bending, but is attributed to the image charge effect of the metal tip, which significantly shifts the band edges of the TiO2(110) towards the Femi level (EF) during the tunneling process. This work not only sheds new lights onto the understanding of plasmon-enhanced light emission of semiconductor surfaces, but also opens up a new avenue for engineering the plasmon-mediated interfacial charge transfer in molecular and semiconducting materials.

Key words: scanning tunneling microscopy, light emission, TiO2, plasmon

中图分类号:  (Electron states at surfaces and interfaces)

  • 73.20.-r
73.20.Mf (Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)) 74.55.+v (Tunneling phenomena: single particle tunneling and STM) 78.60.Fi (Electroluminescence)