Amorphous metal oxide semiconductor phototransistors (MOTPs) integrated with colloidal quantum dots (QDs) (QD-MOTPs) are promising infrared photodetectors owing to their high photoconductive gain, low off-current level, and high compatibility with pixel circuits. However, to date, the poor mobility of conventional MOTPs, such as indium gallium zinc oxide (IGZO), and the toxicity of lead (Pb)-based QDs, such as lead sulfide and lead selenide, has limited the commercial applications of QD-MOTPs. Herein, an ultrasensitive QD-MOTP fabricated by integrating a high-mobility zinc oxynitride (ZnON)–based MOTP and lead-free indium arsenide (InAs) QDs is demonstrated. A new gradated bandgap structure is introduced in the InAs QD layer that absorbs infrared light, which prevents carriers from moving backward and effectively reduces electron–hole recombination. Chemical, optical, and structural analyses confirm the movement of the photoexcited carriers in the graded band structure. The novel QD-MOTP exhibits an outstanding performance with a responsivity of 1.15 × 105 A W−1 and detectivity of 5.32 × 1016 Jones at a light power density of 2 µW cm−2 under illumination at 905 nm.
Bibliographical noteFunding Information:
J.‐H.K. and B.K.J. contributed equally to this work. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2022R1A2C2006887) and the Global Research Laboratory (GRL) program through the National Research Foundation (NRF) of Korea (NRF‐2017K1A1A2013160). This work was also supported by the Creative Materials Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF‐2018M3D1A1059001), the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT, and Future Planning (2022R1A2C4001517) and the Samsung Electronics Co., Ltd. (IO201210‐08027‐01).
© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.
- high mobility
- hybrid phototransistor
- low persistent photoconductivity effect
- near-infrared photodetection
- non-toxic materials
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Chemical Engineering(all)
- Materials Science(all)
- Biochemistry, Genetics and Molecular Biology (miscellaneous)
- Physics and Astronomy(all)