Well separated trion and neutral excitons on superacid treated MoS2 monolayers

被引：55

作者：

Cadiz, Fabian ^{[1
]}

Tricard, Simon ^{[1
]}

Gay, Maxime ^{[1
]}

Lagarde, Delphine ^{[1
]}

Wang, Gang ^{[1
]}

Robert, Cedric ^{[1
]}

Renucci, Pierre ^{[1
]}

Urbaszek, Bernhard ^{[1
]}

Marie, Xavier ^{[1
]}

机构：

[1] Univ Toulouse, LPCNO, UPS, CNRS,INSA, 135 Av Rangueil, F-31077 Toulouse, France

来源：

APPLIED PHYSICS LETTERS | 2016年 / 108卷 / 25期

基金：

欧洲研究理事会;

关键词：

VALLEY POLARIZATION; PHOTOLUMINESCENCE;

D O I：

10.1063/1.4954837

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Developments in optoelectronics and spin-optronics based on transition metal dichalcogenide monolayers (MLs) need materials with efficient optical emission and well-defined transition energies. In as-exfoliated MoS2 MLs, the photoluminescence (PL) spectra even at low temperature consist typically of broad, overlapping contributions from neutral, charged excitons (trions) and localized states. Here, we show that in superacid treated MoS2 MLs, the PL intensity increases by up to 60 times at room temperature. The neutral and charged exciton transitions are spectrally well separated in PL and reflectivity at T = 4K, with linewidth for the neutral exciton of 15 meV, but both transitions have similar intensities compared to the ones in as-exfoliated MLs at the same temperature. Time resolved experiments uncover picoseconds recombination dynamics analyzed separately for charged and neutral exciton emissions. Using the chiral interband selection rules, we demonstrate optically induced valley polarization for both complexes and valley coherence for only the neutral exciton. Published by AIP Publishing.

引用

页数：4

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