Abstract
Solution-processed semiconductors that exhibit tunable light absorption and can be directly integrated into state-of-the-art silicon technologies are attractive for near-infrared (NIR) light detection in applications of medical imaging, night vision cameras, hyperspectral sensing, etc. Colloidal quantum dot (CQD) is regarded as a promising candidate for its solution-processability and superior optoelectronic properties. Here we propose an on-chip CQD photodetector, photodiode-oxide-semiconductor field-effect transistor, for NIR light sensing. This CMOS compatible device architecture utilizes silicon as a channel for carrier transport and PbS CQD as the light absorbing material controlling the channel conductivity. While the light with a wavelength longer than about 1100 nm cannot excite a photocurrent in commercial silicon-based photodetectors due to the absorption cutoff of silicon, the proposed photodetector can have responses owing to the usage of a PbS CQD photodiode. Simulations showed that the photodiode could provide photovoltage to the semiconductor, forming an inversion layer at the oxide-semiconductor interface, and the electron density at the interface is significantly enhanced. As a result, currents could flow through this layer with ease between the source and drain electrodes. For a proof-of-concept demonstration, we experimentally connected a CQD photodiode with a commercial silicon transistor and proved that the current from the transistor could be increased by photovoltage provided by the photodiode under NIR light illumination. The device shows a responsivity of 5.9A/W at the wavelength of 1250 nm.
© 2019 Optical Society of America
Full Article | PDF ArticleMore Like This
Ming-Hao Kuo, Wei-Ting Lai, Sheng-Wei Lee, Yen-Chun Chen, Chia-Wei Chang, Wen-Hao Chang, Tzu-Min Hsu, and Pei-Wen Li
Opt. Lett. 40(10) 2401-2404 (2015)
Shoichiro Fukushima, Masaaki Shimatani, Satoshi Okuda, Shinpei Ogawa, Yasushi Kanai, Takao Ono, Koichi Inoue, and Kazuhiko Matsumoto
Opt. Lett. 44(10) 2598-2601 (2019)
Daniel Popa, Syed Zeeshan Ali, Richard Hopper, Ying Dai, and Florin Udrea
Opt. Lett. 44(17) 4111-4114 (2019)