Single-crystal, 4-inch and ultrathin gallium oxide for sundial-inspired high-dimensional solar-blind photodetection metasystem.

Abstract

Ultra-wide bandgap gallium oxides offer tremendous possibilities to develop short-wave optoelectronic devices. However, it is formidably challenging to produce single-crystal gallium oxide wafer and develop high-performance high-dimensional optoelectronics. Here we show a liquid-metal-assisted strategy to directly synthesize and transfer single-crystal, large-area and ultrathin β-Ga₂O₃. Benefiting from the UV-exposure oxidation of liquid gallium and strong interaction with gallium, our β-Ga₂O₃ film shows a 4-inch wafer-scale size, a 7.5-nm thickness and a flexible transfer operation. The solar-blind β-Ga₂O₃ detector achieves high responsivity (16.3 A W^-1), fast response (<150 μs) and wide linear dynamic range (120 dB). By employing metasurface design, the anisotropy ratio reaches a record high value of 28.8 for Ga₂O₃-based detectors. Moreover, we develop a sundial-inspired metasystem to simultaneously detect the incident direction, polarization, and intensity of solar-blind irradiation. These findings illustrate the potential of high-quality Ga₂O₃ wafer for high-dimensional photodetection, paving the way for next-generation solar-blind communications.