Controlling the surface photovoltage on WSe2 by surface chemical modification

Ro Ya Liu, Kenichi Ozawa, Naoya Terashima, Yuto Natsui, Baojie Feng, Suguru Ito, Wei Chuan Chen, Cheng Maw Cheng, Susumu Yamamoto, Hiroo Kato, Tai Chang Chiang, Iwao Matsuda

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The surface photovoltage (SPV) effect is key to the development of opto-electronic devices such as solar-cells and photo-detectors. For the prototypical transition metal dichalcogenide WSe2, core level and valence band photoemission measurements show that the surface band bending of pristine cleaved surfaces can be readily modified by adsorption with K (an electron donor) or C60 (an electron acceptor). Time-resolved pump-probe photoemission measurements reveal that the SPV for pristine cleaved surfaces is enhanced by K adsorption, but suppressed by C60 adsorption, and yet the SPV relaxation time is substantially shortened in both cases. Evidently, adsorbate-induced electronic states act as electron-hole recombination centers that shorten the carrier lifetime.

Original languageEnglish
Article number211603
JournalApplied Physics Letters
Volume112
Issue number21
DOIs
Publication statusPublished - 2018 May 21

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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