Abstract
By the photodetector manufactured using traditional semiconductor materials, such as HgCdTe and InGaAs, it is difficult to broaden the application range of such photodetectors due to their high cost and complex manufacturing process. PbSe colloidal quantum dots (CQDs) have the potential to shift the working range of photodetector from visible to infrared wavelength region, and it also has high photoresponsivity. Herein, we report the characterization of PbSe CQDs synthesized using a facile solution process, as well as the relationship between the size of nanocrystal and the reaction temperature. The films of PbSe CQDs are deposited using the layer-by-layer (LbL) spin-coating method, which is then used to fabricate the photoconductive device. The fabricated device is found to have an efficient response in a broad spectrum range of 400-2600 nm. The device maintains good responsivity of ~320 mA/W at room temperature. Its external quantum efficiency was quite high in the shorter wavelength infrared region, and it has approximately 14% external quantum efficiency (EQE) at 2520 nm. The device demonstrated excellent performance, confirming that PbSe colloidal quantum dots is a promising material for future broadband spectrum photodetectors.
Highlights
In recent years, the broadband spectrum photodetectors have piqued the interest of researchers working in a variety of fields, including environmental monitoring, biological sensing, and digital cameras [1,2,3,4,5]
This paper reports the synthesis and characterization of PbSe colloidal quantum dots (CQDs) developed by a facile solution process
As the reaction temperature rises from 140°C to 190°C, the size of PbSe CQDs increases, and the synthesized PbSe CQDs aggregate into quadrilateral or round shapes
Summary
The broadband spectrum photodetectors have piqued the interest of researchers working in a variety of fields, including environmental monitoring, biological sensing, and digital cameras [1,2,3,4,5]. The lack of suitable materials that can absorb light ranging from the visible to SWIR has hampered the development of broad-spectrum photodetectors. Traditional semiconductors, such as InGaAs and HgCdTe, are commonly used to fabricate near-to-mid infrared (IR) photodetectors. Xiao et al fabricated a colloidal quantum dot heterojunction-based infrared photodetector This device has an EQE of 40% when using QDs with the longest absorption wavelength of 1600 nm [14]. A PbSe colloidal quantum dot-based infrared photodetector with room temperature responsivities of 64.17 mA/W has been reported, but with a narrow optical spectrum ranging from. The proposed device is expected to replace the existing near-infrared (IR) photodetector and serve as a benchmark for future broad-spectrum photodetectors
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