High-Performance ε-Ga₂O₃ Solar-Blind Ultraviolet Photodetectors With Interdigital Framework

Abstract

We successfully fabricated a high-performance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -Ga2O3 solar-blind photodetector employing an interdigital structure. The device exhibits a prominent response peak at 240 nm with a cutoff edge located at 266 nm. Notably, the solar-blind ultraviolet (UV) in-band/ out-of-band rejection ratio reaches <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{5}}$ </tex-math></inline-formula> , while the photo-to-dark-current ratio (PDCR) exceeds <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{5}}$ </tex-math></inline-formula> . Further-more, we investigate the impact of varying interdigital spacing on device performance. It is observed that decreasing the interdigital spacing leads to an increase in light current and responsivity of the photodetector. Conversely, increasing the spacing contributes to a reduction in dark current. This tradeoff between PDCR and spacing framework indicates that shorter spacing facilitates the construction of wider current channels, thereby enhancing carrier transport and extraction. On the other hand, longer spacing results in an increased area for UV light absorption, subsequently augmenting the number of photogenerated carriers. This work is expected to offer profitable insights for the structural design of wide bandgap semiconductor solar-blind UV photodetectors, leveraging the capabilities of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -Ga2O3.

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