Spatially selective reversible charge carrier density tuning in WS 2 monolayers via photochlorination

//Spatially selective reversible charge carrier density tuning in WS 2 monolayers via photochlorination

Chlorine-doped tungsten disulfide monolayer (1L-WS 2 ) with tunable charge carrier concentration has been realized by pulsed laser irradiation of the atomically thin lattice in a precursor gas atmosphere. This process gives rise to a systematic shift of the neutral exciton peak towards lower energies, indicating reduction of the crystal’s electron density. The capability to progressively tune the carrier density upon variation of the exposure time is demonstrated; this indicates that the Fermi level shift is directly correlated to the respective electron density modulation due to the chlorine species. Notably, this electron withdrawing process enabled the determination of the trion binding energy of the intrinsic crystal, found to be as low as 20 meV, in accordance to theoretical predictions. At the same time, it is found that the effect can be reversed upon continuous wave laser scanning of the monolayer in air. Scanning auger microscopy (SAM) and x-ray photoelectron s…

Published in: "2DMaterials".

2018-10-17T12:37:49+00:00October 17th, 2018|Categories: Publications|Tags: , |
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