Gate-tunable high-performance broadband phototransistor array of two-dimensional PtSe₂ on SOI

Two-dimensional (2D) layered materials have attracted extensive research interest in the field of high-performance photodetection due to their high carrier mobility, tunable bandgap, stability, and other excellent properties. Herein, we propose a gate-tunable, high-performance, self-driving, and wide detection range phototransistor based on a 2D PtSe₂ on silicon-on-insulator (SOI). Benefiting from the strong built-in electric field of the PtSe₂/Si heterostructure, the phototransistor has a fast response time (rise/fall time) of 36.7/32.6 μs. The PtSe₂/Si phototransistor exhibits excellent photodetection performance over a broad spectral range from ultraviolet to near-infrared, including a responsivity of 1.07 A/W and a specific detectivity of 6.60 × 10⁹ Jones under 808 nm illumination at zero gate voltage. The responsivity and specific detectivity of PtSe₂/Si phototransistor at 5 V gate voltage are increased to 13.85 A/W and 1.90 × 10¹⁰ Jones under 808 nm illumination. Furthermore, the fabricated PtSe₂/Si phototransistor array shows excellent uniformity, reproducibility, and long-term stability in terms of photoresponse performance with negligible variation between pixel cells. The architecture of present PtSe₂/Si on SOI platform paves a new way of a general strategy to realize high-performance photodetectors by combining the advantages of both 2D materials and conventional semiconductors which is compatible with current Si-complementary metal oxide semiconductor (CMOS) process.