Complementary Interface Optimization Enabled by Photochemical Passivation and van der Waals Contacts for High-Performance Ultraviolet Photodetectors

Interfacial quality is a key determinant of semiconductor optoelectronic performance, governing carrier transport, recombination, and noise, and often limiting ultimate device figures of merit. To address interfacial constraints, we introduce a damage-free, complementary interface optimization by combining an ultrathin ZrO₂ passivation formed via room-temperature photochemical deposition with van der Waals (vdW) Au contacts. The conformal ZrO₂ interlayer suppresses surface trap states and increases the effective Schottky barrier height to 1.24 eV, whereas vdW metal contacts minimize interfacial damage and mitigate metal-induced gap states. Implemented in GaN ultraviolet photodetectors, this vdW Au/ZrO₂/GaN back-to-back Schottky architecture yields ultralow dark current (∼2 × 10⁻¹³ A), high responsivity (20.26 A/W with internal gain ∼70), fast temporal response (rise time ∼50 μs), and an ultrawide linear dynamic range of 141.47 dB. Specific detectivity exceeds 1 × 10¹² Jones under the 1/f noise limit, corresponding to a noise-equivalent power on the order of 10⁻¹⁴ W. Benchmarking against state-of-the-art GaN Schottky photodiodes and commercial UV detectors shows improvements of one to three orders of magnitude in key performance metrics. This room-temperature, solution-processable, vacuum-free strategy integrates damage-free vdW contacts with photochemical dielectric passivation to reduce interface state density and enhance carrier transport, providing a versatile and scalable platform for high-performance wide-bandgap optoelectronic devices.