Fig. 3: Proposed mechanisms of optical property enhancement due to dodecanol encapsulation.
From: Macroscopic transition metal dichalcogenides monolayers with uniformly high optical quality
a Comparison of PL spectra of bare (black), only bottom-covered (blue), only top-covered (green), and both top and bottom-covered (red) MoSe2 MML. b, c Comparison of X-ray photoelectron spectroscopy (XPS) spectra of (b) Mo 3d core levels and (c) Se 3d core levels of the same four MMLs as in (a), showing blueshifts when there is top-coverage of dedocanol (green and red). d–g Illustration of the effects of dodecanol on the MoSe2 MML optical properties. d Bare MoSe2 MML suffers from in-gap state (IGS) emission (small red wavy arrow) due to exciton trapped at Se vacancies and PL quenching (black arrow) due to disorders in substrate. e Bottom dodecanol layer separates MoSe2 from the substrate. f Top dodecanol layer passivates Se vacancies and leads to band-edge PL emission (blue wavy arrow). g Top and bottom layers complete the encapsulation.
