Chemical trends of deep levels in van der Waals semiconductors

Penghong Ci, Xuezeng Tian, Jun Kang, Anthony Salazar, Kazutaka Eriguchi, Sorren Warkander, Kechao Tang, Jiaman Liu, Yabin Chen, Sefaattin Tongay, Wladek Walukiewicz, Jianwei Miao, Oscar Dubon, Junqiao Wu

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Properties of semiconductors are largely defined by crystal imperfections including native defects. Van der Waals (vdW) semiconductors, a newly emerged class of materials, are no exception: defects exist even in the purest materials and strongly affect their electrical, optical, magnetic, catalytic and sensing properties. However, unlike conventional semiconductors where energy levels of defects are well documented, they are experimentally unknown in even the best studied vdW semiconductors, impeding the understanding and utilization of these materials. Here, we directly evaluate deep levels and their chemical trends in the bandgap of MoS2, WS2 and their alloys by transient spectroscopic study. One of the deep levels is found to follow the conduction band minimum of each host, attributed to the native sulfur vacancy. A switchable, DX center - like deep level has also been identified, whose energy lines up instead on a fixed level across different hosts, explaining a persistent photoconductivity above 400 K.

Original languageEnglish (US)
Article number5373
JournalNature communications
Issue number1
StatePublished - Dec 1 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • General
  • Physics and Astronomy(all)


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