Highly sensitive SWIR photodetector using carbon nanotube thin film transistor gated by quantum dots heterojunction

Low-dimensional semiconductors have been considered excellent materials to construct photodetectors for infrared detection with an easy process and excellent compatibility but suffer from low detectivity mainly owing to the poor light absorption of the ultra-thin body. Here, we demonstrate a thin film transistor (TFT) based short-wave infrared photodetector consisting of a carbon nanotube (CNT) TFT gated by a PbS colloidal quantum dots (CQDs) based heterojunction. The thick PbS CQDs' film efficiently absorbs infrared light and then excites and separates electron-hole pairs to generate a photovoltage at the pn heterojunction of the PbS CQDs/ZnO film. The photovoltage is further amplified and transduced in situ by the CNT TFT under the heterojunction, and then the detector featured a specific detectivity of 5.6 x 10(13) Jones under 1300 nm illumination and a fast response of the sub-ms level (0.57 ms). The CQDs based heterojunction gating TFT represents a universal architecture for highly sensitive low-dimensional semiconductor based infrared photodetectors, competitive with state-of-the-art epitaxial semiconductors and enabling monolithic integration technology.Published under an exclusive license by AIP Publishing

Automated summary

This study demonstrates a thin film transistor (TFT) based short-wave infrared photodetector using a heterojunction of carbon nanotubes (CNT) and PbS colloidal quantum dots (CQDs). The CQDs efficiently absorb infrared light and generate a photovoltage at the heterojunction, which is further amplified and transduced by the CNT TFT. The detector shows high sensitivity and fast response, making it competitive with state-of-the-art epitaxial semiconductors.