Surface Oxidation Doping to Enhance Photogenerated Carrier Separation Efficiency for Ultrahigh Gain Indium Selenide Photodetector

Yih Ren Chang, Po Hsun Ho, Cheng Yen Wen, Tzu Pei Chen, Shao Sian Li, Jhe Yi Wang, Min Ken Li, Che An Tsai, Raman Sankar, Wei Hua Wang, Po Wen Chiu, Fang Cheng Chou, Chun Wei Chen

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


This work presents an ultrahigh gain InSe-based photodetector by using a novel approach called the surface oxidation doping (SOD) technique. The carrier concentration of multilayered two-dimensional (2D) InSe semiconductor surface has been modulated by controlling the formation of a surface oxide layer. The SOD through surface charge transfer at the interface of the oxide/2D InSe semiconductor heterostructure can lead to the creation of a vertical built-in potential and band bending as a result of the carrier concentration distribution gradient. The internal electric field caused by the formation of a carrier concentration gradient in InSe layers can facilitate charge separation of photogenerated electron-hole pairs under light illumination. Consequently, the record high photoresponsivities of InSe-based photodetector with ∼5 × 106 A/W at the excitation wavelength of 365 nm and 5 × 105 A/W at the wavelength of 530 nm can be obtained, outperforming the majority of photodetectors based on other 2D materials, such as graphene, MoS2, and even highly sensitive multilayer GaTe and In2Se3 flakes. The approach based on SOD induced efficient photogenerated charge separation can be also applied to other 2D layered semiconductors.

Original languageEnglish
Pages (from-to)2930-2936
Number of pages7
JournalACS Photonics
Issue number11
Publication statusPublished - Nov 15 2017
Externally publishedYes


  • field effect transistor
  • indium selenide
  • p-doping
  • photodetector
  • surface oxidation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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