Ultrafast carbon nanotube photodetectors with bandwidth over 60 GHz

TL;DR

This paper presents a CMOS-compatible carbon nanotube photodetector with over 60 GHz bandwidth, high responsivity, and broad spectral operation, suitable for high-speed optical interconnects in data centers.

Contribution

It demonstrates a doping-free, scalable CNT photodetector with ultrafast response and broad spectral coverage, advancing integration with CMOS technology.

Findings

Bandwidth over 60 GHz achieved

Successfully transmitted 100 Gbit/s Nyquist-shaped signals

Compatible with CMOS fabrication processes

Abstract

The future interconnect links in intra- and inter-chip require the photodetector with high bandwidth, ultra-wide waveband, compact footprint, low-cost, and compatible integration process with silicon complementary metal-oxide-semiconductor (CMOS) technology. Here, we demonstrate a CMOS-compatible carbon nanotube (CNT) photodetector that exhibits high responsivity, high bandwidth and broad spectral operation over all optical telecommunication band based on high-purity CNT arrays. The ultrafast CNT photodetector demonstrates the 100 Gbit/s Nyquist-shaped on-off-keying (OOK) signal transmission, which can address the demand for high-speed optical interconnects in and between data centers. Furthermore, the photodetector exhibits a bandwidth over 60 GHz by scaling down the active area to 20 {\mu}m2. As the CNT photodetectors are fabricated by doping-free process, it also provides a cost-effective solution to integrate CNT photonic devices with CNT-based CMOS integrated circuits. Our work paves a way for future CNT-based high-speed optical interconnects and optoelectronic integrated circuits (OEICs).