Multilayered PdTe₂/GaN Heterostructures for Visible-Blind Deep-Ultraviolet Photodetection

Deep-ultraviolet (DUV) photodetection has garnered extensive research interest for its vital applications in many military and civil fields. In this work, we present the synthesis of a large-area two-dimensional (2D) PdTe₂ multilayer, which can be directly transferred onto a GaN substrate to construct a vertical heterostructure for visible-blind DUV photodetection. Upon 265 nm light irradiation, the heterostructure displays a distinct photovoltaic behavior, enabling it to serve as a self-driven photodetector. The important photoresponse parameters, such as <inline-formula> <tex-math notation="LaTeX">${I}_{light}/{I}_{dark}$ </tex-math></inline-formula> ratio, responsivity, specific detectivity and DUV/visible (265 nm/450 nm) rejection ratio reach as high as 10⁶, 168.5 mA/W, <inline-formula> <tex-math notation="LaTeX">$5.3 \times 10^{12}$ </tex-math></inline-formula> Jones, and 10⁴, respectively, at zero bias. The responsivity can be further enhanced to 254.6 mA/W by applying a small reverse bias of −1.0 V. In addition, the photodetector can function as a DUV light image sensor to reliably record an “H” pattern with a decent resolution. The present study paves a way for designing high-performance cost-effective DUV photodetectors towards practical optoelectronic applications.