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) is a semi-metallic two-dimensional (2D) material that can be synthesized below 450 °C. We integrate PtSe-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 for PDs far into the IR wavelength range. Our PtSe PDs integrated by direct growth outperform PtSe 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 an attractive 2D material for optoelectronics and PICs.