Dissociation of two-dimensional excitons in monolayer WSe2

被引：140

作者：

Massicotte, Mathieu ^{[1
]}

Vialla, Fabien ^{[1
]}

Schmidt, Peter ^{[1
]}

Lundeberg, Mark B. ^{[1
]}

Latini, Simone ^{[2
,3
]}

Haastrup, Sten ^{[2
]}

Danovich, Mark ^{[4
]}

Davydovskaya, Diana ^{[1
]}

Watanabe, Kenji ^{[5
]}

Taniguchi, Takashi ^{[5
]}

Fal'ko, Vladimir I. ^{[3
]}

Thygesen, Kristian S. ^{[2
,3
]}

Pedersen, Thomas G. ^{[6
,7
]}

Koppens, Frank H. L. ^{[1
,8
]}

机构：

[1] Barcelona Inst Sci & Technol, ICFO Inst Ciencies Foton, Barcelona 08860, Spain

[2] Tech Univ Denmark, Dept Phys, CAMD, DK-2800 Lyngby, Denmark

[3] Tech Univ Denmark, CNG, DK-2800 Lyngby, Denmark

[4] Univ Manchester, Natl Graphene Inst, Booth St E, Manchester M13 9PL, Lancs, England

[5] Natl Inst Mat Sci, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan

[6] Aalborg Univ, Dept Phys & Nanotechnol, DK-9220 Aalborg, Denmark

[7] CNG, DK-9220 Aalborg, Denmark

[8] ICREA, Barcelona 08010, Spain

来源：

NATURE COMMUNICATIONS | 2018年 / 9卷

基金：

加拿大自然科学与工程研究理事会; 英国工程与自然科学研究理事会; 新加坡国家研究基金会;

关键词：

GIANT BANDGAP RENORMALIZATION; OPTOELECTRONICS; ANNIHILATION; GENERATION; IONIZATION; GRAPHENE; DIODES;

D O I：

10.1038/s41467-018-03864-y

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Two-dimensional (2D) semiconducting materials are promising building blocks for optoelectronic applications, many of which require efficient dissociation of excitons into free electrons and holes. However, the strongly bound excitons arising from the enhanced Coulomb interaction in these monolayers suppresses the creation of free carriers. Here, we identify the main exciton dissociation mechanism through time and spectrally resolved photocurrent measurements in a monolayer WSe2 p-n junction. We find that under static inplane electric field, excitons dissociate at a rate corresponding to the one predicted for tunnel ionization of 2D Wannier-Mott excitons. This study is essential for understanding the photoresponse of 2D semiconductors and offers design rules for the realization of efficient photodetectors, valley dependent optoelectronics, and novel quantum coherent phases.

引用

页数：7

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