Photonic integrated circuits, or PICs, use photons to carry information and have high transmission speeds, low delays, and anti-electromagnetic crosstalk. These benefits are expected to address the problems with microelectronics chips’ speed, power consumption and integration density. This is crucial for promoting breakthroughs and quantum information technology in microelectronics, micro-sensing, and microelectronics in the “post-Moore era”.
Photonic integrated chips are making great strides today, thanks to the use of information technology. Silicon PIC can be used with mature CMOS technology to produce low-cost, large-scale production. Silicon nitride PIC can tolerate moderately high optical power and large fabrication errors, and Lithium niobate PIC can achieve perfect electro-optic modulations using low driven voltages and high linearity. However, the monolithic integration waveguides/photodetectors with a single component are one of their major weaknesses. The PIC materials can’t absorb light, so it is impossible to create integrated photodetectors from a single material. Hetero-integrations solved this problem (e.g., Ge, III-V compound semiconductors etc.) of bulk absorptive materials. On-chip PICs have been successfully implemented. It still faces challenges due to the high cost, complex fabrication processes and material interface problems. Two-dimensional (2D), photon-absorbing materials for chip-integrated photodetectors have been popularized recently. Two-dimensional (2D) materials do not have any surface dangling bond, so there are no lattice-mismatch restrictions to hetero-integrate them using PICs. Many electronic and optical properties are available in the 2D material family, including black phosphorus, semi-metallic graphene and insulating boron. The appropriate 2D materials can be used to build chip-integrated photodetectors that operate at different spectral ranges.
A new paper published in the journal Light Science & Application was published by a research team led by Professor Xuetao Gan, Key Laboratory of Light Field Manipulation and Information Acquisition Ministry of Industry and Information Technology. The paper, published on April 20, 2022, in the journal Light Science & Application, reports that van der Waals PN heterojunctions of two-dimensional materials on optical waveguides could be a promising strategy for chip-integrated photodetectors.
Researchers can create van der Waals heterostructures using the 2D layered structure without dangling links and “stacking” wood to stack 2D materials of different properties differently. Van der Waals heterojunctions that can be “arbitrarily combined” can give advantages to a single material and also create new properties.
The preparation of source-drain electrodes can be integrated onto the photonic platform using the “stacking timber” technology. They can be placed on both sides without the need for cumbersome processes like photolithography.
This greatly simplifies the manufacturing process and prevents contamination of the interface during processes like photolithography. This greatly enhances the device’s performance.
