Two-dimensional materials have attracted much interest for realizing novel optoelectronic devices, e.g., photodetectors. In this work, we demonstrate a high-performance black-phosphorus avalanche photodetector based on a silicon hybrid plasmonic waveguide with double nanoslots, in which way the light absorption by black phosphorus is enhanced and the carrier transit time is reduced simultaneously. Benefiting from the avalanche multiplication process in black phosphorus, the present waveguide avalanche photodetector exhibits high responsivities of 66 A/W (@optical power of 2.9 μW) and 125 A/W (@optical power of 1.4 μW) for the wavelength bands of 1.55 and 1.95 μm, respectively. The measured 3 dB-bandwidth is 1.05 GHz, which is at least three orders of magnitude higher than those reported high-gain photodetectors based on two-dimensional materials. The present high-performance silicon/BP waveguide avalanche photodetector provides a promising option toward the applications of optical sensing, optical imaging, and optical communications in the wavelength band of 1.55/1.95 μm and even beyond.

High-sensitivity and high-bandwidth receivers are always demanded for high-speed optical link systems. As a key element, an avalanche photodiode (APD) is often regarded as one of the most attractive options for achieving high sensitivity owing to the potential high internal gain. In this paper, a 48-GHz waveguide Ge/Si avalanche photodiode operating at the O-band (1310 nm) is designed with a lateral reach-through structure and fabricated with simplified processes. The fabricated APD shows a high primary responsivity of 0.93 A/W at the unit-gain voltage of − 4.7 V . It has an avalanche gain of 12.8 and a record gain-bandwidth product of ∼ 615 GHz with an input optical power of − 15 dBm when operating at a bias voltage of − 14 V . The present Ge/Si APD is used successfully for high-speed data receiving, showing a sensitivity improvement about 7.6 dB for KP4-FEC operation (i.e.,  BER = 2.4 × 10 − 4 ) with 50 Gbps non-return-to-zero (NRZ) data, compared with the case of using the reference PIN PD on the same chip. The sensitivity of the receiver with the present APD for NRZ signals is about − 21.3 dBm , − 17.8 dBm , and − 12.6 dBm for KP4-FEC operation with different data rates of 50 Gbps, 80 Gbps, and 100 Gbps, while the sensitivity for four-level pulse amplitude modulation signals is about − 13.2 dBm and − 11.3 dBm for KP4-FEC operation with different data rates of 25 and 50 Gbaud. Such high-performance APDs pave the way to achieve high-speed and high-sensitivity data transmissions.

2D materials (2DMs) meet the demand of broadband and low‐cost photodetection on silicon for many applications. Currently, it is still very challenging to realize excellent silicon‐2DM photodetectors (PDs). Here, graphene–silicon–graphene waveguide PDs operating at the wavelength bands of 1.55 and 2 µm, showing the potential for large‐scale integration, are demonstrated. For the fabricated PDs, the measured responsivities are ≈0.15 and ≈0.015 mA W−1 for the wavelengths of 1.55 and 1.96 µm, respectively. In particular, the PDs exhibit a high bandwidth of ≈30 GHz, an ultra‐low dark current of tens of pico‐amperes, a high normalized photo‐to‐dark‐current ratio of 1.63 × 106 W−1, as well as a high linear dynamic range of 3 µW to 1.86 mW (and beyond) at 1.55 µm. According to the measurement results for the wavelength bands of 1.55/2.0 µm and the theoretical modeling for the silicon–graphene heterostructure, it is revealed that internal photoemission and photo‐assisted thermionic field emission dominantly contribute to the photoresponse in the graphene–silicon Schottky junctions under moderately high bias voltage, which helps the future work to further improve the performance.

A high-performance waveguide Ge/Si avalanche photodiode operating at the O-band (1310 nm) is designed with a Ge/Si ridge waveguide defined by two shallow trenches in the active region and fabricated with simplified processes. The device shows a high primary responsivity of 0.96 A/W at the unit-gain voltage of −7.5 V. It has a large 3-dB bandwidth of >27 GHz and a low dark current of 1.8 µA at a reverse bias voltage of −13 V. When the present Ge/Si APD is used for receiving 25 Gbps data, the eye-diagram is open even for an optical power as low as −18 dBm. Furthermore, 50 Gbps data receiving is also demonstrated with an input optical power of −15 dBm, showing the great potential of the present Ge/Si APD for the application in future high-speed data transmission systems.