Platinum Disulfide (PtS₂) and Silicon Pyramids: Efficient 2D/3D Heterojunction Tunneling and Breakdown Diodes

p–n junctions constructed from the group-10 TMDCs, or namely, transition metal dichalcogenides with an intrinsic layered structure, are not considerably reported. This study presents a mechanical exfoliation-based technique to prepare PtS2/Si pyramid p–n junctions for an investigation of tunneling and breakdown diodes. The demonstrated p–n diode exhibited a high rectifying performance reaching a rectification ratio (If/Ir) of ∼7.2 × 104 at zero gate bias with an ideality factor of ∼1.5. The Zener tunneling was observed at a low reverse bias region of breakdown voltage (from −6 to −1.0 V) at various temperatures (50 to 300 K), and it was a negative coefficient of temperature. Conversely, for the greater breakdown voltage regime (−15 to −11 V), the breakdown voltage increased with the increased temperature (200 to 300 K), indicating a positive coefficient of temperature. Therefore, this phenomenon was attributed to the avalanche breakdown. The p–n junctions displayed photovoltaic characteristics under the illumination of visible light (500 nm), such as a high responsivity (Rph) and a photo gain (G) of 11.88 A/W and 67.10, respectively. The maximum values for both the open-circuit voltage (VOC) and the short-circuit current (ISC) were observed to be 0.45 V and 10 μA, respectively, at an input intensity of light of 70.32 mW/cm2. The outcomes of this study suggest that PtS2/ Si pyramid p–n junctions may be employed in numerous optoelectronic devices including photovoltaic cells, Zener tunneling diodes, avalanche breakdown diodes, and photodetectors.