Abstract
Monolayer transition metal dichalcogenides (TMDs) are direct gap semiconductors with promising applications in diverse optoelectronic devices. To improve devices’ performance, recent investigations have been systematically focused on the tuning of their optical properties. However, an all-optical approach with the reversible feature is still a challenge. Here we demonstrate the tunability of the photoluminescence (PL) properties of monolayer WS2 via laser irradiation. The broad-range and continuous modulation of PL intensity, as well as the conversion between neutral and charged excitons have been readily and reversibly achieved by only switching the two laser power densities. We attribute the reversible manipulation to the laser-assisted adsorption and desorption of gas molecules, which will deplete or release free electrons from the surface of WS2 and thus modify its PL properties. This all-optical manipulation, with advantages of reversibility, quantitative control, and high spatial resolution, suggests promising applications of TMDs monolayers in optoelectronic and nanophotonic applications, such as erasable optical data storage, micropatterning, and display.
Highlights
Thin two-dimensional (2D) transition metal dichalcogenides (TMDs) with the chemical formula MX2 (M = Mo, W, and X = S, Se) have attracted great interest recently, due to their unique electric and optical properties as well as their potential applications in diverse optoelectronic devices [1,2]
The contaminants and impurities are always inevitably introduced during the fabrication of the field-effect transistor (FET) structure, which may significantly reduce the performance of optoelectronic devices
Isolated flakes with a triangular shape and edge lengths ranging from 10 to 20 μm can be clearly obserIvsoelda.teTdhfelakthesicwknitehssa otrfiatnhgeuslearWshSa2pfleaakneds ehdagsebleenengthesxpralonrgeindgbfyroamto1m0 itcof2o0rcμemmciacnrobsecoclpeyarl(yAFM) charaocbtesreirzvaetdio. nT,haestshhicokwnenssinofFitghuesree W1bS.2Tflhaeketshihcaksnbeesesnofex−p0l.o8rendmby(thaetocmroicssfosreccetimonicrhoesicgohptyis(ApFreMs)ented in thecinhinathrsaeectit)nescreioztn)atcfiioornnmf,isarmstshshatohtwathtntehineflFafilkagkeueriesis1aab.mmToohnenotohllaiacyykeenrre[2s[s32]o3.f]T.−h0Te.8hrneelmartei(lvtaheteliyvcrheoloysmshsoeogcmetniooenoguhesenicegoohluot irssccpoorneltosreranscttoeidnntrast in thethAe FAMFMimimaaggee aallssoo iinnddiiccaatetsesthtahtatthethbeasbaalspallanpelaonfethoef mthoenomlaoynerolWaySe2 risWflaSt2ainsdfluantifaonrmd .uWneiform
Summary
Thin two-dimensional (2D) transition metal dichalcogenides (TMDs) with the chemical formula MX2 (M = Mo, W, and X = S, Se) have attracted great interest recently, due to their unique electric and optical properties as well as their potential applications in diverse optoelectronic devices [1,2] Compared to their bulk crystals and the multilayer form, monolayer MX2 are direct gap semiconductors and manifest bright photoluminescence (PL) in the visible region even at room temperature [3]. The contaminants and impurities are always inevitably introduced during the fabrication of the FET structure, which may significantly reduce the performance of optoelectronic devices It can be partly avoided by using molecular physisorption gating, while the vacuum conditions and pumping apparatus impede their extensive applications [18]. The manipulation of excitons and trions, PL intensity, as well as PL spectra, can be reversibly manipulated by only switching the high and the low power densities of irradiation laser, which provides promising applications in erasable data storage
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call