Asymmetric Schottky Contacts Enhanced Two-Dimensional Heterojunctions for Self-Powered Broadband and...

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Schottky junction photodetectors offer low cost and rapid response for self-powered photodetection.
• Challenges include Fermi-level pinning, defect states, and leakage current, hindering performance.
• Asymmetric Schottky contacts are explored to improve modulation and rectification.

Purpose of the Study:

• To develop a self-powered broadband and polarization-sensitive photodetector.
• To enhance rectification performance and mitigate Fermi-level pinning.
• To leverage the anisotropy of 2D materials for advanced photodetection.

Main Methods:

• Fabrication of an enhanced Au/2H-MoTe₂/1T'-MoTe₂ heterojunction.
• Utilizing van der Waals material 1T'-MoTe₂ to address Fermi-level pinning.
• Investigating the in-plane anisotropy of 1T'-MoTe₂ for polarization sensitivity.

Main Results:

• Achieved a rectification ratio exceeding 10⁴, significantly improving performance.
• Demonstrated wavelength-dependent photocurrent anisotropy ratios from 2.61 to 5.4.
• Exhibited broadband photodetection from 405 to 2200 nm at zero bias.
• Reported a peak On/Off ratio of 5.97 × 10⁴, responsivity of 80.59 mA/W, EQE of 15.14%, and detectivity of 1.05 × 10¹² Jones.

Conclusions:

• The proposed heterojunction effectively overcomes limitations of traditional photodetectors.
• The device exhibits high performance, broadband, and polarization-sensitive photodetection capabilities.
• This work provides insights for developing next-generation advanced photodetectors.