Xiao-Wei Tong, Ya-Nan Lin,a Rui Huang, Zhi-Xiang Zhang, Can Fu, Di Wu, Lin-Bao Luo,* Zhong-Jun Li,

* Feng-Xia Liang,c Wei Zhang*

Abstract:Platinum telluride (PtTe₂) has garnered significant research interest due to its unique properties. However, the large-scale synthesis and PtTe₂ potential in optoelectronic devices have not been explored yet. Herein, we report direct tellurization of Pt nanofilms to synthesize large-area PtTe₂ films and the influence of tellurization temperature and gas flow rate on morphology and chemical structure of PtTe₂ is systematically investigated. The electrical analysis reveals that the as-grown PtTe₂ films exhibit typical semi-metallic characteristics, which are consistent with the results of first-principles density functional theory (DFT) calculations. Moreover, the combination of multilayered PtTe₂ and Si results in the formation of PtTe₂/Si heterojunction, exhibiting rectifying behavior with the rectification ratio of 10⁴ at ±1 V. Moreover, PtTe₂-based photodetectors displays broadband sensitivity to light illumination, ranging from 200 to 1650 nm, with peak sensitivity at the wavelength of 980 nm. The responsivity, specific detectivity and external quantum efficiency of PtTe₂-based photodetector are found to be 0.406 A W^-1, 3.62´10¹² Jones and 32.1%, respectively. What is more, the response speed of τ_raise and τ_fall is estimated to be 7.51 μs and 36.7 μs, respectively. Finally, an image sensor, consisting of 8´8 PtTe₂-based photodetectors array, which is able to record five near-infrared (NIR) images under the 980 nm with satisfying resolution. These result demonstrates that the present PtTe₂ material may find potential application in future NIR optoelectronics.