PtTe₂‐Based Type‐II Dirac Semimetal and Its van der Waals Heterostructure for Sensitive Room Temperature Terahertz Photodetection

TLDR

Recent advances in two‑dimensional materials have highlighted their potential for photodetection, yet achieving long‑wavelength, high‑temperature, and fast‑responsivity operation remains challenging, and topological materials offer new opportunities for such devices. The study aims to directly generate photocurrent in the low‑energy terahertz band at room temperature using a planar metal–PtTe₂–metal structure. The device employs a planar metal–PtTe₂–metal architecture to produce the photocurrent. The PtTe₂ detector delivers a bias‑free photoresponsivity of 1.6 A W⁻¹ with a <20 µs response, while a PtTe₂–graphene heterostructure achieves >1.4 kV W⁻¹ and <9 µs, enabling large‑area imaging and demonstrating PtTe₂ as a promising topological semimetal for high‑performance THz photodetection.

Abstract

Abstract Recent years have witnessed rapid progresses made in the photoelectric performance of two‐dimensional materials represented by graphene, black phosphorus, and transition metal dichalcogenides. Despite significant efforts, a photodetection technique capable for longer wavelength, higher working temperature as well as fast responsivity, is still facing huge challenges due to a lack of best among bandgap, dark current, and absorption ability. Exploring topological materials with nontrivial band transport leads to peculiar properties of quantized phenomena such as chiral anomaly, and magnetic‐optical effect, which enables a novel feasibility for an advanced optoelectronic device working at longer wavelength. In this work, the direct generation of photocurrent at low energy terahertz (THz) band at room temperature is implemented in a planar metal–PtTe 2 –metal structure. The results show that the THz photodetector based on PtTe 2 with bow‐tie‐type planar contacts possesses a high photoresponsivity (1.6 A W −1 without bias voltage) with a response time less than 20 µs, while the PtTe 2 –graphene heterostructure‐based detector can reach responsivity above 1.4 kV W −1 and a response time shorter than 9 µs. Remarkably, it is already exploitable for large area imaging applications. These results suggest that topological semimetals such as PtTe 2 can be ideal materials for implementation in a high‐performing photodetection system at THz band.