High-performance broadband heterojunction photodetectors based on multilayered PtSe2 directly grown on a Si substrate

Abstract

Two-dimensional group-10 transition metal dichalcogenides have recently attracted increasing research interest because of their unique electronic and optoelectronic properties. Herein, we present vertical hybrid heterojunctions of multilayered PtSe₂ and Si, which take advantage of large-scale homogeneous PtSe₂ films grown directly on Si substrates. These heterojunctions show obvious rectifying behavior and a pronounced photovoltaic effect, enabling them to function as self-driven photodetectors operating at zero bias. The photodetectors can operate in both photovoltage and photocurrent modes, with responsivity values as high as 5.26 × 10⁶ V W⁻¹ and 520 mA W⁻¹ at 808 nm, respectively. The I_light/I_dark ratio, specific detectivity, and response speed are 1.5 × 10⁵, 3.26 × 10¹³ Jones, and 55.3/170.5 μs, respectively. Furthermore, the heterojunctions are highly sensitive in a broad spectral region ranging from deep ultraviolet to near-infrared (NIR) (200–1550 nm). Because of the strong NIR light absorption of PtSe₂, the heterojunctions exhibit photocurrent responsivities of 33.25 and 0.57 mA W⁻¹ at telecommunication wavelengths of 1310 and 1550 nm, respectively. Considering the excellent performance of the PtSe₂/Si heterojunctions, they are highly suitable for application in high-performance broadband photodetectors. The generality of the above results also signifies that the proposed in situ synthesis method has great potential for future large-scale optoelectronic device integration.