Wide Spectral Photoresponse of Layered Platinum Diselenide-Based Photodiodes

Platinum diselenide (PtSe₂) is a group-10 transition metal dichalcogenide (TMD) that has unique electronic properties, in particular a semimetal-to-semiconductor transition when going from bulk to monolayer form. We report on vertical hybrid Schottky barrier diodes (SBDs) of two-dimensional (2D) PtSe₂ thin films on crystalline n-type silicon. The diodes have been fabricated by transferring large-scale layered PtSe₂ films, synthesized by thermally assisted conversion of predeposited Pt films at back-end-of-the-line CMOS compatible temperatures, onto SiO₂/Si substrates. The diodes exhibit obvious rectifying behavior with a photoresponse under illumination. Spectral response analysis reveals a maximum responsivity of 490 mA/W at photon energies above the Si bandgap and relatively weak responsivity, in the range of 0.1-1.5 mA/W, at photon energies below the Si bandgap. In particular, the photoresponsivity of PtSe₂ in infrared allows PtSe₂ to be utilized as an absorber of infrared light with tunable sensitivity. The results of our study indicate that PtSe₂ is a promising option for the development of infrared absorbers and detectors for optoelectronics applications with low-temperature processing conditions.