Open AccessSolution Processed Hybrid Polymer: HgTe Quantum Dot Phototransistor with High Sensitivity and Fast Infrared Response up to 2400 nm at Room Temperature
Author(s) -
Dong Yifan,
Chen Mengyu,
Yiu Wai Kin,
Zhu Qiang,
Zhou Guodong,
Kershaw Stephen V.,
Ke Ning,
Wong Ching Ping,
Rogach Andrey L.,
Zhao Ni
Publication year - 2020
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.202000068
Subject(s) - materials science , photodiode , optoelectronics , photodetector , photodetection , specific detectivity , infrared , quantum dot , passivation , active layer , dark current , optics , layer (electronics) , nanotechnology , thin film transistor , physics
Narrow bandgap semiconductor‐based photodetectors often suffer from high room‐temperature noise and are therefore operated at low temperatures. Here, a hybrid poly(3‐hexylthiophene) (P3HT): HgTe quantum dot (QD) phototransistor is reported, which exhibits high sensitivity and fast photodetection up to 2400 nm wavelength range at room temperature. The active layer of the phototransistor consists of HgTe QDs well dispersed in a P3HT matrix. Fourier‐transform infrared spectra confirm that chemical grafting between P3HT and HgTe QDs is realized after undergoing prolonged coblend stirring and a ligand exchange process. Thanks to the shifting of the charge transport into the P3HT and the partial passivation of the surface traps of HgTe QDs in the blend, the P3HT: HgTe QD hybrid phototransistor shows significantly improved gate‐voltage tuning, 15 times faster response, and ≈80% reduction in the noise level compared to a pristine HgTe QD control device. More than 10 11 Jones specific detectivity (estimated from the noise spectral density measured at 1 kHz) is achieved at room temperature, and the response time (measured at 22 mW cm −2 illumination intensity) of the device is less than 1.5 µs. That is comparable to commercial epitaxially grown IR photodetectors operated in the same wavelength range.