Complementary Interface Optimization Enabled by Photochemical Passivation and van der Waals Contacts for...

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Interfacial quality critically impacts semiconductor optoelectronic device performance, affecting carrier transport, recombination, and noise.
• Existing methods often introduce damage or limitations at semiconductor interfaces, hindering ultimate device capabilities.
• Gallium Nitride (GaN) based devices are crucial for ultraviolet (UV) optoelectronics but are sensitive to interfacial defects.

Purpose of the Study:

• To introduce a damage-free interface optimization strategy for wide-bandgap semiconductors.
• To improve the performance of Gallium Nitride (GaN) ultraviolet photodetectors by addressing interfacial constraints.
• To develop a versatile and scalable platform for high-performance optoelectronic devices.

Main Methods:

• Combined ultrathin zirconium dioxide (ZrO2) passivation via room-temperature photochemical deposition with van der Waals (vdW) gold contacts.
• Fabricated a vdW Au/ZrO2/GaN back-to-back Schottky architecture.
• Characterized device performance including dark current, responsivity, temporal response, linear dynamic range, and specific detectivity.

Main Results:

• Achieved effective Schottky barrier height of 1.24 eV and suppressed surface trap states with ZrO2 interlayer.
• Minimized interfacial damage and metal-induced gap states using vdW Au contacts.
• Demonstrated ultralow dark current (~2 × 10^-13 A), high responsivity (20.26 A/W), fast response (~50 μs), and ultra-wide dynamic range (141.47 dB).
• Specific detectivity exceeded 1 × 10^12 Jones, with noise-equivalent power on the order of 10^-14 W.
• Performance metrics showed improvements of one to three orders of magnitude compared to state-of-the-art devices.

Conclusions:

• The room-temperature, solution-processable, vacuum-free strategy effectively reduces interface state density and enhances carrier transport.
• The integrated approach of photochemical dielectric passivation and damage-free vdW contacts provides a scalable platform for advanced optoelectronics.
• This method offers significant performance enhancements for GaN-based UV photodetectors and other wide-bandgap devices.