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Thickness-dependent ultrafast nonlinear absorption properties of PtSe2 films with both semiconducting and semimetallic phases

Authors :
Yang Yao
Chang-Fu Huo
Wangwei Hui
Dongqi Liu
Junfang Xie
Zhi-Bo Liu
Xin Zhao
Xiao-Qing Yan
Qing Ye
Fang Liu
Chengcheng Guo
Jianguo Tian
Source :
Applied Physics Letters. 115:263102
Publication Year :
2019
Publisher :
AIP Publishing, 2019.

Abstract

The bandgap, electrical, and optical properties of PtSe2 depend dramatically on the vertical stacking and fabrication method. Here, we study the nonlinear absorption properties of the PtSe2 films composed of both semiconducting and semimetallic phases in a single film. These PtSe2 films exhibit remarkable thickness-dependent saturable absorption for femtosecond pulses at 400 nm and 800 nm. The saturation intensities decrease with the increase in the film thickness due to the accompanied increase in the semimetallic component and are much smaller than the reported values of PtSe2 synthesized by thermally assisted conversion. The saturable absorption characteristics are confirmed by time-resolved spectroscopies. The nonlinear refractive indexes of these PtSe2 films should be smaller than 1 × 10–12 cm2/W. Our results imply that the optical nonlinearities of PtSe2 could be flexibly tuned by the synthesis method and thickness.

Details

ISSN :
10773118 and 00036951
Volume :
115
Database :
OpenAIRE
Journal :
Applied Physics Letters
Accession number :
edsair.doi...........def907ba3230c942ba077bfa1bb7fee4
Full Text :
https://doi.org/10.1063/1.5135375