Evolution of the electronic band structure and efficient photo-detection in atomic layers of InSe

Sidong Lei, Liehui Ge, Sina Najmaei, Antony George, Rajesh Kappera, Jun Lou, Manish Chhowalla, Hisato Yamaguchi, Gautam Gupta, Robert Vajtai, Aditya D. Mohite, Pulickel M. Ajayan

Research output: Contribution to journalArticlepeer-review

379 Scopus citations


Atomic layers of two-dimensional (2D) materials have recently been the focus of extensive research. This follows from the footsteps of graphene, which has shown great potential for ultrathin optoelectronic devices. In this paper, we present a comprehensive study on the synthesis, characterization, and thin film photodetector application of atomic layers of InSe. Correlation between resonance Raman spectroscopy and photoconductivity measurements allows us to systematically track the evolution of the electronic band structure of 2D InSe as its thickness approaches few atomic layers. Analysis of photoconductivity spectra suggests that few-layered InSe has an indirect band gap of 1.4 eV, which is 200 meV higher than bulk InSe due to the suppressed interlayer electron orbital coupling. Temperature-dependent photocurrent measurements reveal that the suppressed interlayer interaction also results in more localized p z-like orbitals, and these orbitals couple strongly with the in-plane E′ and E″ phonons. Finally, we measured a strong photoresponse of 34.7 mA/W and fast response time of 488 μs for a few layered InSe, suggesting that it is a good material for thin film optoelectronic applications.

Original languageEnglish (US)
Pages (from-to)1263-1272
Number of pages10
JournalACS Nano
Issue number2
StatePublished - Feb 25 2014

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


  • 2D layered materials
  • InSe
  • photoconductivity
  • photodetector
  • resonance Raman scattering


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