State‐of‐the‐art all‐silicon sub‐bandgap photodetectors at telecom and datacom wavelengths

Abstract

Silicon-based technologies provide an ideal platform for the monolithic integration of photonics and microelectronics. In this context, a variety of passive and active silicon photonic devices have been developed to operate at telecom and datacom wavelengths, at which silicon has minimal optical absorption -due to its bandgap of 1.12 eV. Although in principle this transparency window limits the use of silicon for optical detection above 1.1 µm, in recent years tremendous advances have been achieved in the field of all-silicon subbandgap photodetectors at telecom and datacom wavelengths -by taking advantage of new emerging materials and structures. In this paper, a review of the state of the art is presented.Devices based on defect-mediated absorption, two-photon absorption and the internal photoemission effect are reported, their working principles are elucidated and their performance discussed and compared.

Harvesting the loss: surface plasmon-based hot electron photodetection

“…In addition, the tunability of the plasmonic structures enables a straightforward means to tailor the response of a photodetector including the working wavelength, bandwidth, and polarization dependence [44,46,48,49]. For more information on general sub-bandgap photodetection we point the reader to a recent review on the topic [92]. and silicon, with the ability to detect near-infrared light below the silicon bandgap energy [44] (Figure 2A).…”

Enhanced Photoelectric and Photothermal Responses on Silicon Platform by Plasmonic Absorber and Omni‐Schottky Junction

“…In the above studies, the photodetectors were operated without external bias, where the hot electron was identified to be the dominant photoresponse mechanism. However, based on previous reports, other mechanisms can contribute, and in some cases even dominate the response in electrically biased interband photodetectors . Among them, the photothermoelectric (PTE) and bolometric effects are more relevant in plasmonic device systems with both of these two mechanisms thermally driven.…”

“…These approaches however have significant drawbacks such as thermal mismatch, the complexity in fabrication, high cost and integration issues. Aiming at all‐silicon based NIR photodetection, trap‐assisted absorption, two photon absorption and impurity‐mediated sub‐band gap response mechanisms have been investigated …”

Highly Efficient Excitation of Surface Plasmons Using a Si Gable Tip

“…In fact, a pair of Si gable tips can be used in conjunction as a source and receiver for the SPP waves as shown in Figure (b). Furthermore, plasmonic detectors based of internal photo‐emission (IPE) process are widely investigated for designing efficient detectors for Si photonic circuitry . Due to the compactness and high efficiency (thereby enhancing the IPE) of the SPP excitation scheme at the telecom wavelength, it can find application in designing such detectors for integrated photonics.…”

“…Furthermore, plasmonic detectors based of internal photoemission (IPE) process are widely investigated for designing efficient detectors for Si photonic circuitry. [25][26][27] Due to the compactness and high efficiency (thereby enhancing the IPE) of the SPP excitation scheme at the telecom wavelength, it can find application in designing such detectors for integrated photonics. The proposed gabled Si tip SPP excitation scheme can also be useful in enhanced nonlinear applications.…”