Probing the photocurrent in two-dimensional titanium disulfide

Ruan Zhang; Shuangxing Zhu; Jiaxin Wu; Yijie Fan; Binghe Xie; Jianqiao Meng; Xinghan Cai

doi:10.1088/1361-6528/ad0054

Probing the photocurrent in two-dimensional titanium disulfide

Nanotechnology. 2023 Oct 20;35(1). doi: 10.1088/1361-6528/ad0054.

Authors

Ruan Zhang^{1

2}, Shuangxing Zhu^{1

2}, Jiaxin Wu^{1

2}, Yijie Fan^{1

2}, Binghe Xie^{1

2}, Jianqiao Meng³, Xinghan Cai¹

Affiliations

¹ National Key Laboratory of Advanced Micro and Nano Manufacture Technology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
² Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
³ School of Physics, Central South University, Changsha 410083, Hunan, People's Republic of China.

PMID: 37797583
DOI: 10.1088/1361-6528/ad0054

Abstract

Generating photocurrent in a condensed matter system involves the excitation, relaxation, and transportation of charge carriers. As such, it is viewed a potent method for probing the dynamics of non-equilibrium carriers and the electronic band structure of solid state materials. In this research, we analyze the photoresponse of the mechanically exfoliated titanium disulfide (TiS₂), a transition metal dichalcogenide whose classification as either a semimetal or a semiconductor has been the subject of debate for years. The scanning photocurrent microscopy and the temperature-dependent photoresponse characterization expose the appearance of a photovoltaic current primarily from the metal/TiS₂junction in an unbiased sample, while negative photoconductivity due to the bolometric effect is observed in the conductive TiS₂channel. The optoelectronic experimental results, combined with electrical transport characterization and angle-resolved photoemission spectroscopy measurements, indicate that the TiS₂employed in this study is likely a heavily-doped semiconductor. Our findings unveil the photocurrent generation mechanism of two dimensional TiS₂, highlighting its prospective optoelectronic applications in the future.

Keywords: SPCM; bolometric effect; photovoltaics; thin-film TiS2.