Recent progress in waveguide-integrated photodetectors based on 2D materials for infrared detection

Abstract

Two-dimensional(2D) materials have received extensive attention in optoelectronics because of their unique characteristics. However, due to the extremely thin thickness of 2D materials, their optical absorption is limited. In recent years, researchers have used different effects and structures to enhance the optical absorption of 2D materials. Waveguide, as a device to guide and limit light propagation, has been integrated into photodetectors based on 2D materials, and most of them are applied in the infrared spectrum. This article reviews the development of waveguide-integrated photodetectors based on 2D materials, mainly in the infrared spectrum in recent years. Discussions mainly focus on the preparation of materials in waveguide-integrated photodetectors, the design and simulation of waveguide structures, and the research results and applications of waveguide-integrated photodetectors in recent years are summarized. Finally, the challenges and prospects of waveguide-integrated photodetectors are put forward and discussed.

On-chip two-dimensional material-based waveguide-integrated photodetectors

“…Also, silicon waveguides possess low propagation losses of less than 0.5 dB cm À1 , enabling nearly lossless optical signals to be transmitted over long distances. 113,114 In addition, silicon serves as a foundation material for CMOS processes, allowing compatibility with existing siliconintegrated circuits. Furthermore, its thermal and chemical stability also make it suitable for various operating environments and fabrication conditions.…”

“…15,115 Additionally, their refractive index of 1.98 ensures a relatively larger refractive index, facilitating the realization of compact waveguide dimensions, and their lower relative permittivity also facilitates smaller device capacitance, making them more suitable for fabricating high-speed devices. 15,114 Silicon and silicon nitride are ideal materials for the fabrication of on-chip optoelectronic devices, offering functionalities such as optical coupling, modulation, detection, and switching. Accordingly, integrating them with 2DMs is an effective solution to achieve efficient photodetection.…”

“…In the PC effect, light changes the conductivity of materials, and the photocurrent can be detected by an applied electric field. 114,141 When operated in the dark and without bias, the dark current in PC effect-based PDs is close to zero due to the absence of a built-in electric field or presence of a feeble built-in electric field. When subjected to illumination and bias, photons with energy higher than the bandgap excite electron-hole pairs, which drift in opposite directions under the influence of an external electric field.…”

Photodetectors integrating waveguides and semiconductor materials

“…Thus, to achieve integrated photoelectric chips, photodetectors integrating waveguides and semiconductor materials have attracted increasing attention as a promising solution. [14][15][16] Fig. 1 shows an outline of this article, which mainly reviews the advanced work on photodetectors integrating waveguides and semiconductor materials, focusing on waveguide materials, waveguide types, semiconductor materials and integrated-waveguide photodetector types.…”

High responsivity all-fiber-integrated perovskite photodetector based on FA0.4MA0.6PbI3

“…The waveguide-coupled AFPD is a low-loss photodetector based on evanescent field coupling 5 . As the photodetector is part of the waveguide, it not only exhibits the advantage of low insertion loss but also extends the effective absorption distance of the active layer, showing a "long-range effect" that enhances device's responsivity 6 .…”