Significant Enhancement of Single-Walled Carbon Nanotube Based Infrared Photodetector Using PbS Quantum Dots

We show that the performance of single-walled carbon nanotubes (SWCNTs) based infrared photodetector can be greatly enhanced through the combination with colloidal PbS quantum dots (QDs). To improve the photo-induced charge transport efficiency and the carrier mobility, the colloidal PbS QDs are modified by short-chain inorganic. Under illumination, the light-induced electron-hole pairs can be effectively separated by the internal electric field formed at the interfaces between SWCNTS and PbS QDs, which will lead to the increase of both conductivities in them. Photocurrent is formed under the driving of source-drain voltage (
V
_ds
) applied by the interdigital finger electrodes. Our hybrid phototransistor achieves a responsivity of 7.2 A/W, a specific detectivity (defined below) of 7.1×10
¹⁰
Jones, and a response time of 1.58 ms at the same time under 1550-nm illumination with low intensity. Through gate voltage tuning, the responsivity can be increased to 353.4 A/W. In addition, our hybrid phototransistor is stable, low-cost, and compatible with complementary metal oxide semiconductor, which benefits a lot in real applications.