A high performance self-powered photodetector based on a 1D Te-2D WS₂ mixed-dimensional heterostructure

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• One-dimensional (1D)-two-dimensional (2D) van der Waals (vdWs) mixed-dimensional heterostructures offer atomically sharp interfaces and high quality.
• These heterostructures are gaining significant attention for their unique electronic and optoelectronic properties.

Purpose of the Study:

• To construct and investigate a novel mixed-dimensional vertical heterostructure.
• To evaluate the photovoltaic effect and self-powered photodetector capabilities of the fabricated heterostructure.

Main Methods:

• Fabrication of a mixed-dimensional vertical heterostructure by transferring mechanically exfoliated 2D WS₂ nanosheets onto epitaxially grown 1D Te microwires.
• Characterization of the heterostructure's optoelectronic properties, including photovoltaic effect and photodetector performance under illumination.

Main Results:

• The 1D Te-2D WS₂ heterostructure exhibits a photovoltaic effect with an open-circuit voltage (V_oc) up to ~0.2 V.
• The self-powered photodetector (SPPD) demonstrates high photoresponsivity (471 mA W⁻¹), external quantum efficiency (91%), and detectivity (1.24 × 10¹² Jones) at 635 nm.
• Achieved a high light-to-dark current ratio (I_light/I_dark) of 10⁴ with suppressed dark current to the sub-pA level, and fast response times (25 ms rise, 14.7 ms decay).

Conclusions:

• The 1D Te-2D WS₂ mixed-dimensional heterostructures show excellent potential for high-performance self-powered photodetectors.
• The demonstrated properties suggest significant application prospects in advanced photodetector and photovoltaic devices.