Ultrafast Photocurrent Response and High Detectivity in Two-Dimensional MoSe₂-based Heterojunctions

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenide (TMDC) materials exhibit unique properties for advanced technologies.
• TMDCs enable high-performance heterostructures with novel interfacial phenomena.
• MoSe2-based heterojunctions are promising for optoelectronic applications.

Purpose of the Study:

• To investigate ultrafast photoresponse in MoSe2-based heterostructures.
• To compare optoelectronic properties of MoSe2 with WSe2 and MoS2.
• To understand photocurrent generation mechanisms and optimize device performance.

Main Methods:

• Fabrication of MoSe2-based heterostructures with p-doped WSe2 and MoS2.
• Measurement of photocurrent signals and photoresponse time constants.
• Analysis of carrier mobility, Schottky barriers, and interface states.

Main Results:

• Observed ultrafast photoresponse with a time constant of ~16 μs in MoSe2-WSe2 and MoSe2-MoS2 heterojunctions.
• Achieved a high detectivity of ~10^14 Jones, exceeding industry standards.
• Identified high carrier mobility in MoSe2 and reduced interface barriers as key factors for fast response.

Conclusions:

• MoSe2-based heterostructures exhibit significantly enhanced photoresponse speeds.
• The fast response is attributed to MoSe2's carrier mobility and favorable heterojunction properties.
• These findings pave the way for next-generation high-performance 2D optoelectronic devices.