Abstract
Photodetectors are the fundamental building blocks for many optoelectronic systems, including night vision, optical communications, biomedical imaging, security and motion detection. Carbon nanotubes (CNTs), which have a direct-bandgap structure, a broad spectral response and a large absorption coefficient, provide an ideal research platform for the exploration of high-performance infrared photodetectors. In the past twenty years, great efforts have been devoted to improve detection sensitivity via adopting high-purity CNT films, various doping strategies, optical manipulations and sensitizing nanostructures. Despite considerable strides made, challenges remain in simultaneously achieving high responsivity, low dark current and fast response. In this Review, we summarize recent advances on key device construction strategies and underlying concepts that contribute to improve performance of fabricated CNT photodetectors. The newly emerging heterojunction gated CNT transistors and their potential are highlighted to overcome trade-offs between the optical and electronic processes. Novel applications of CNT photodetectors are further summarized for advanced optoelectronic technologies.