Light-Induced Depletion-Region Modulation in a PtTe₂/Ga₂O₃ Schottky Junction Field-Effect Transistor for Solar-Blind...

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Solar-blind phototransistors are crucial for applications requiring detection in the ultraviolet spectrum.
• Traditional phototransistors often suffer from high dark currents and noise, limiting their performance.
• Gallium oxide (β-Ga₂O₃) is a promising material for deep-ultraviolet optoelectronics due to its wide bandgap.

Purpose of the Study:

• To develop a high-performance solar-blind phototransistor with suppressed dark current and enhanced photocurrent.
• To investigate the use of a platinum telluride (PtTe₂) semimetal gate for a dielectric-free van der Waals (vdW) Schottky contact.
• To characterize the optoelectronic properties of the novel PtTe₂/β-Ga₂O₃ phototransistor.

Main Methods:

• Fabrication of a top-gate β-Ga₂O₃ metal-semiconductor field-effect transistor (MESFET) with a PtTe₂ gate.
• Utilizing a van der Waals (vdW) Schottky contact between PtTe₂ and β-Ga₂O₃.
• Electrical and photoresponse measurements to evaluate device performance.

Main Results:

• The PtTe₂/β-Ga₂O₃ phototransistor exhibited minimal hysteresis (80 mV) and an extremely low OFF-state current (≈10 fA).
• Achieved an ON/OFF current ratio exceeding 10⁸, a record photo-to-dark current ratio of 1.13 × 10⁹, and high responsivity (6.75 × 10⁴ A/W).
• Demonstrated high external quantum efficiency (3.3 × 10⁷ %) and specific detectivity (4.46 × 10¹⁵ Jones).

Conclusions:

• The top-gate design effectively modulates the depletion region, suppressing dark current.
• The synergistic response of the PtTe₂/β-Ga₂O₃ interface enhances photocurrent generation.
• This PtTe₂/β-Ga₂O₃ phototransistor presents a promising route for developing high-performance solar-blind optoelectronic devices.