Carrier Dynamics in the Space Charge Layer of MoS2 Flakes Studied by Time-Resolved μ-Surface Photovoltage

Liang，Yu1,4; Zhang，Guanhua1; Sun，Julong1; Zhou，Chuanyao1; Li，Ziling2; Ye，Yu2; Yang，Xueming1,3; Ren，Zefeng1

2023

10.1021/acs.jpcc.3c00055

Journal of Physical Chemistry C   Impact Factor & Quartile

1932-7447

1932-7455

Carrier dynamics in the space charge layer (SCL) is an important topic in semiconductor science, especially for the promising two-dimensional semiconductor materials used in next-generation electronic and optoelectronic devices. Investigating these materials on both spatial and ultrafast time scales is crucial to promote their widespread application. Here, we systematically study the carrier dynamics of MoS flakes using femtosecond time-resolved spectroscopic photoemission electron microscopy. By acquiring a series of microarea photoelectron spectra at various time delays, we obtain the time-resolved microarea surface photovoltage (μ-SPV), which reflects the carrier dynamics in the SCL. Our findings show that the dynamics strongly depends on temperature and carrier density. At low temperature, the decay of SPV exhibits a significantly slow rate, that is limited by the low thermionic emission. A high pump fluence causes a large SPV maximum and a plateau that lasts only for tens of ps and is followed by a fast decay, while a low pump fluence results in a small SPV maximum with a plateau or a slow increase for longer than ns. These results arise from different competing mechanisms among carrier trapping, detrapping, diffusion, and electron-hole recombination. Our study demonstrates that time-resolved μ-SPV is an effective method for investigating charge carrier dynamics in layered semiconductor materials, offering valuable insight into the photophysical processes within the SCL.

SCI

English

Others

Ministry of Science and Technology of China[2018YFA0208700 and2021YFA1500600] ; National Natural Science Foundation of China["22073097","U1832202"]

Chemistry ; Science & Technology - Other Topics ; Materials Science

Chemistry, Physical ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary

WOS:000971552300001

AMER CHEMICAL SOC

2-s2.0-85152206917

Scopus

1.State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian,457 Zhongshan Road, Liaoning,116023,China
2.School of Physics,Peking University,Beijing,100871,China
3.Department of Chemistry,Southern University of Science and Technology,Guangdong,1088 Xueyuan Road, Shenzhen,518055,China
4.University of Chinese Academy of Sciences,Beijing,19 A Yuquan Road,100049,China

Liang，Yu,Zhang，Guanhua,Sun，Julong,et al. Carrier Dynamics in the Space Charge Layer of MoS2 Flakes Studied by Time-Resolved μ-Surface Photovoltage[J]. Journal of Physical Chemistry C,2023.

Liang，Yu.,Zhang，Guanhua.,Sun，Julong.,Zhou，Chuanyao.,Li，Ziling.,...&Ren，Zefeng.(2023).Carrier Dynamics in the Space Charge Layer of MoS2 Flakes Studied by Time-Resolved μ-Surface Photovoltage.Journal of Physical Chemistry C.

Liang，Yu,et al."Carrier Dynamics in the Space Charge Layer of MoS2 Flakes Studied by Time-Resolved μ-Surface Photovoltage".Journal of Physical Chemistry C (2023).