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

Abstract

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 × 1013 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.

Enhancement-Mode Carbon Nanotube Optoelectronic Synaptic Transistors with Large and Controllable Threshold Voltage Modulation Window for Broadband Flexible Vision Systems

“…For example, various photosensitive materials including dyes, chlorophyll, and photosensitive quantum dots (QDs) have been reported to construct SWCNT synaptic transistors. QDs with high photochemical stability and tunable bandgaps are regarded as an effective strategy for creating artificial synaptic devices. − However, many reported QDs have posed a potential threat to the environment during the large-scale production, highlighting the importance of developing environmentally friendly QDs synaptic devices. Additionally, the addition of QDs into the channel often leads to the degradation of electrical performance, including the decrease in conductivity causing reduced open-state current, the increase in subthreshold swing (SS), threshold voltage shifts, and noticeable hysteresis phenomena.…”