A collaborated team led by Prof. LI Liang and Prof. LI Guanghai at the Hefei Institutes of Physical Science (HFIPS) of the Chinese Academy of Sciences (CAS), together with Prof. YAN Feng from Hong Kong Polytechnic University, has recently developed a new two-dimensional (2D)-based photodetector with ultrafast photoresponse and broadband detection capabilities.

The photodetector, introduced in a paper recently published in ACS Nano, was made from layered ternary telluride InSiTe₃.

Photodetectors with broadband detection capabilities play a crucial role in our daily lives and are widely used in various applications. Many 2D materials-based photodetectors exhibit high photoresponsivity and detectivity but slow response speed due to their prolonged excess carrier lifetime. Such slow speed performance has become the bottleneck for 2D materials-based photodetectors in practical application, especially in optical communication. 

"We found that the response of this InSiTe₃-based photodetector is stable and reversible." said Prof. LI Liang.

The promising photodetector is based on ternary telluride InSiTe₃ with trigonal symmetry and a layered structure. Scientists synthesized high-quality InSiTe₃ crystals and determined its Raman vibration modes by Raman spectra measurements.

In their experiments, the response of the photos was between 545-576 ns, and the detection capability was between 365-1,310 nm in the communication region from ultraviolet to near-infrared light.   

They also found that the indirect band gap of InSiTe₃ could be tuned from 1.30 eV (monolayer) to 0.78 eV (bulk). Moreover, the InSiTe₃-based photodetectors exhibit the detectivity of 7.59 × 109 Jones.

These outstanding performance values highlight the potential of 2D InSiTe₃-based photodetectors in high-speed broadband photodetection.

This research was supported by the Natural Science Foundation of China, the Recruitment Program for Leading Talent Team of Anhui Province, the Natural Science Foundation of Anhui Province, the Open Research Fund of Advanced Laser Technology Laboratory of Anhui Province, and the Hong Kong Polytechnic University.

Left. photoresponse spectra curves at different wavelength irradiation; Right. comparison of speed performance and spectral response with other reported 2DM-based photodetectors. (Image by LI Liang) 

Prototype device for point phtodetection base on 2D InSiTe₃. (Image by LI Liang)