Low breakdown field and high ionization index in ReSe₂ avalanche field-effect transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Avalanche field-effect transistors (AFETs) using 2D materials show promise for optoelectronics due to carrier multiplication.
• Existing 2D material AFETs are limited by low breakdown fields and ionization indexes.

Purpose of the Study:

• To develop a high-performance AFET with enhanced breakdown field and ionization index.
• To explore the use of anisotropic ReSe2 and HfZrO2 in AFETs for improved optoelectronic applications.

Main Methods:

• Fabrication of a ReSe2-based AFET utilizing anisotropic ReSe2 as the channel material.
• Incorporation of HfZrO2 as a high-k dielectric to improve gate modulation.
• Validation of the mechanism through electron effective mass calculations and scattering probability simulations.

Main Results:

• Achieved a breakdown electric field of 2.55 kVcm⁻¹ and an ionization index of 38.79.
• Demonstrated ReSe2 avalanche phototransistors with responsivity of 1.71×10⁴ AW⁻¹ and gain of 173.
• Reduced carrier collisions and scattering effects by using anisotropic ReSe2 and HfZrO2.

Conclusions:

• Anisotropic ReSe2 and HfZrO2 integration significantly enhances AFET performance.
• This design offers a viable route for developing high-performance avalanche photodetectors.
• The study validates the mechanism of reduced carrier scattering in anisotropic 2D materials.