Two-Dimensional Platinum Diselenide Waveguide-Integrated Infrared Photodetectors.

Low-cost, easily integrable photodetectors (PDs) for silicon (Si) photonics are still a bottleneck for photonic-integrated circuits (PICs), especially for wavelengths above 1.8 μm. Multilayered platinum diselenide (PtSe 2 ) is a semi-metallic two-dimensional (2D) material that can be synthesized below 450 °C. We integrate PtSe 2 -based PDs directly by conformal growth on Si waveguides. The PDs operate at 1550 nm wavelength with a maximum responsivity of 11 mA/W and response times below 8.4 μs. Fourier-transform IR spectroscopy in the wavelength range from 1.25 to 28 μm indicates the suitability of PtSe 2 for PDs far into the IR wavelength range. Our PtSe 2 PDs integrated by direct growth outperform PtSe 2 PDs manufactured by standard 2D layer transfer. The combination of IR responsivity, chemical stability, selective and conformal growth at low temperatures, and the potential for high carrier mobility makes PtSe 2 an attractive 2D material for optoelectronics and PICs.