Ultra-sensitive solution-processed broadband photodetectors based on vertical field-effect transistor.

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• IV-VI semiconductor colloidal quantum dots (e.g., PbSe, PbS, PbSSe) are crucial for infrared photodetectors due to their photosensitivity and cost-effective fabrication.
• Field-effect transistor (FET) based photodetectors offer high detectivity by amplifying current, but traditional lateral designs suffer from low photosensitivity and slow response.

Purpose of the Study:

• To develop novel vertical FET (VFET) based photodetectors with improved performance for infrared detection.
• To overcome the limitations of traditional lateral FET photodetectors, such as low photosensitivity and slow responsivity.

Main Methods:

• Fabrication of VFET photodetectors with the active layer sandwiched between a porous source electrode and a planar drain electrode, creating an ultrashort channel.
• Characterization of photodetector performance under specific illumination intensities and applied voltages.

Main Results:

• Achieved enhanced photoresponsivity of 291 A W^-1 and specific detectivity of 1.84 × 10¹⁴ Jones.
• Demonstrated superior performance compared to traditional lateral FET photodetectors at a drain-source voltage of -1 V and gate voltage of -2 V under 100 μW cm^-2 illumination.

Conclusions:

• The developed VFET photodetectors exhibit high performance and stability, making them promising for broadband infrared detection.
• The VFET architecture provides an effective approach for fabricating high-performance, stable photodetectors using an easy fabrication method.