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Tailoring of Bound Exciton Photoluminescence Emission in WS 2 Monolayers
Author(s) -
Kaupmees Reelika,
Grossberg Maarja,
Ney Marcel,
Asaithambi Aswin,
Lorke Axel,
Krustok Jüri
Publication year - 2020
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201900355
Subject(s) - photoluminescence , exciton , monolayer , materials science , excitation , band gap , blueshift , chemical vapor deposition , metalorganic vapour phase epitaxy , molecular physics , optoelectronics , condensed matter physics , atomic physics , chemistry , epitaxy , physics , nanotechnology , layer (electronics) , quantum mechanics
Temperature‐ and laser power‐dependent photoluminescence (PL) properties of the asymmetric defect‐bound exciton bandX Din defective WS 2 monolayers, grown by chemical vapor deposition, are studied. Based on PL mapping, a monolayer region with an intensiveX Dband emission at about 1.9 eV is chosen for further studies. TheX Dband is thermally quenched above 180 K, and the thermal activation energy is found to beE a = 33 ± 4 meV. At T = 15 K, theX Dband intensity reveals a sublinear dependence with increasing excitation power and the peak position shows a blueshift of about 15 meV per decade of laser power. It is shown that theX Dband is related to the deep defect states within the band gap of WS 2 .