Ultrafast Exciton and Spin Dynamics of Monolayer MoSi2N4 Studied by Non-Degenerate Pump-Probe Transient Transmission Spectroscopy

被引：0

作者：

Wu, Huiping ^{[1
]}

Sun, Su ^{[2
]}

Xu, Chuan ^{[2
]}

Chen, Ke ^{[1
,3
]}

Ren, Wencai ^{[2
]}

Lai, Tianshu ^{[1
]}

机构：

[1] Sun Yat Sen Univ, Sch Phys, State Key Lab Optoelect Mat & Technol, Guangzhou 510275, Guangdong, Peoples R China

[2] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China

[3] Sun Yat Sen Univ, Ctr Neutron Sci & Technol, Sch Phys, Guangdong Prov Key Lab Magnetoelectr Phys & Device, Guangzhou 510275, Peoples R China

来源：

ADVANCED SCIENCE | 2025年

基金：

中国国家自然科学基金; 国家重点研发计划;

关键词：

exciton dynamics; monolayer MoSi2N4; spin dynamics; time-resolved Faraday rotation spectroscopy; transient differential transmission spectroscopy; 2D SEMICONDUCTOR; LAYER; LIFETIMES;

D O I：

10.1002/advs.202417209

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

2D materials have attracted numerous attention for their potential applications in nano-photoelectronic and valleytronic devices. Recently, a new 2D material, MoSi2N4 monolayer, is synthesized and reported, and predicted to have many unique properties. Here, its ultrafast photoelectron and spin dynamics using femtosecond-resolved transient differential transmission and Faraday rotation spectroscopies are investigated. Complex and diverse ultrafast dynamics of excitons are observed with increasing probe wavelength from 510 to 640 nm, including fully positive and negative monotonic decaying dynamics as well as an initial positive (negative) peak followed by slow negative (positive) recovery dynamics, and are explained well based on the band structure of MoSi2N4 monolayer containing a deep defect level locating above the midpoint of direct bandgap at K valley. Spin polarization of A and B excitons is found controlled by the circular helicity of exciting light. The spin relaxation lifetime of B excitons is determined as approximate to 0.73 ps.

引用

页数：9