Reversible engineering of topological insulator surface state conductivity through optical excitation

Faji Xie, Zhen Lian, Shuai Zhang, Tianmeng Wang, Shengnan Miao, Zhiyong Song, Zhe Ying, Xing Chen Pan, Mingsheng Long, Minhao Zhang, Fucong Fei, Weida Hu, Geliang Yu, Fengqi Song, Ting Ting Kang, Su Fei Shi

Research output: Contribution to journalArticlepeer-review

Abstract

Despite the broadband response, limited optical absorption at a particular wavelength hinders the development of optoelectronics based on Dirac fermions. Heterostructures of graphene and various semiconductors have been explored for this purpose, while non-ideal interfaces often limit the performance. The topological insulator (TI) is a natural hybrid system, with the surface states hosting high-mobility Dirac fermions and the small-bandgap semiconducting bulk state strongly absorbing light. In this work, we show a large photocurrent response from a field effect transistor device based on intrinsic TI Sn-Bi1.1Sb0.9Te2S (Sn-BSTS). The photocurrent response is non-volatile and sensitively depends on the initial Fermi energy of the surface state, and it can be erased by controlling the gate voltage. Our observations can be explained with a remote photo-doping mechanism, in which the light excites the defects in the bulk and frees the localized carriers to the surface state. This photodoping modulates the surface state conductivity without compromising the mobility, and it also significantly modify the quantum Hall effect of the surface state. Our work thus illustrates a route to reversibly manipulate the surface states through optical excitation, shedding light into utilizing topological surface states for quantum optoelectronics.

Original languageEnglish
Article number17LT01
JournalNanotechnology
Volume32
Issue number17
DOIs
Publication statusPublished - 2021 Feb 5
Externally publishedYes

Keywords

  • Dirac fermion
  • Photodoping
  • Quantum Hall effect
  • Surface states
  • Topological insulator

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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