Direct Tellurization of Pt to Synthesize 2D PtTe₂ for High-Performance Broadband Photodetectors and NIR Image Sensors

Abstract

Platinum telluride (PtTe₂) has garnered significant research enthusiasm owing to its unique characteristics. However, large-scale synthesis of PtTe₂ toward potential photoelectric and photovoltaic application has not been explored yet. Herein, we report direct tellurization of Pt nanofilms to synthesize large-area PtTe₂ films and the influence of growth conditions on the morphology of PtTe₂. Electrical analysis reveals that the as-grown PtTe₂ films exhibit typical semimetallic behavior, which is in agreement with the results of first-principles density functional theory (DFT) simulation. Moreover, the combination of multilayered PtTe₂ and Si results in the formation of a PtTe₂/Si heterojunction, exhibiting an obvious rectifying effect. Moreover, the PtTe₂-based photodetector displays a broadband photoresponse to incident radiation in the range of 200-1650 nm, with the maximum photoresponse at a wavelength of ∼980 nm. The <i>R</i> and <i>D</i>* of the PtTe₂-based photodetector are found to be 0.406 A W^-1 and 3.62 × 10¹² Jones, respectively. In addition, the external quantum efficiency is as high as 32.1%. On the other hand, the response time of τ_rise and τ_fall is estimated to be 7.51 and 36.7 μs, respectively. Finally, an image sensor composed of a 8 × 8 PtTe₂-based photodetector array was fabricated, which can record five near-infrared (NIR) images under 980 nm with a satisfying resolution. The result demonstrates that the as-prepared PtTe₂ material will be useful for application in NIR optoelectronics.