“…To date, MWIR intraband QD photodetectors have only been studied as lateral photoconductive devices, , while advancing the device toward a vertically stacked structure can have great implications in their applications. Specifically, vertically stacked QD devices can enable direct integration of intraband QD technology with existing silicon read-out integrated circuits for fabricating focal plane arrays without hybridization. , From a scientific point of view, the vertical structure enables the incorporation of complex heterostructure QD layer stacks that can be used to modulate carrier distribution and dynamics for improved detector performance.…”
Section: Introductionmentioning
confidence: 99%
“…Specifically, vertically stacked QD devices can enable direct integration of intraband QD technology with existing silicon read-out integrated circuits for fabricating focal plane arrays without hybridization. 14,15 From a scientific point of view, the vertical structure enables the incorporation of complex heterostructure QD layer stacks that can be used to modulate carrier distribution and dynamics for improved detector performance.…”
Intraband quantum dots are degenerately doped semiconductor nanomaterials
that exhibit unique optical properties in mid- to long-wavelength
infrared. To date, these quantum dots have been only studied as lateral
photoconductive devices, while transitioning toward a vertically stacked
structure can open diverse opportunities for investigating advanced
device designs. Here, we report the first vertical intraband quantum
dot heterojunction devices composed of Ag2Se/PbS/Ag2Se quantum dot stacks that bring the advantage of reduced
dark conductivity with a simplified device fabrication procedure.
We discuss the improvement in the colloidal synthesis of Ag2Se quantum dots that are critical for vertical device fabrication,
identify an important process that determines the mid-wavelength infrared
responsivity of the quantum dot film, and analyze the basic device
characteristics and key detector performance parameters. Compared
to the previous generation of Ag2Se quantum dot-based photoconductive
devices, approximately 70 times increase in the mid-wavelength responsivity,
at room temperature, is observed.
“…To date, MWIR intraband QD photodetectors have only been studied as lateral photoconductive devices, , while advancing the device toward a vertically stacked structure can have great implications in their applications. Specifically, vertically stacked QD devices can enable direct integration of intraband QD technology with existing silicon read-out integrated circuits for fabricating focal plane arrays without hybridization. , From a scientific point of view, the vertical structure enables the incorporation of complex heterostructure QD layer stacks that can be used to modulate carrier distribution and dynamics for improved detector performance.…”
Section: Introductionmentioning
confidence: 99%
“…Specifically, vertically stacked QD devices can enable direct integration of intraband QD technology with existing silicon read-out integrated circuits for fabricating focal plane arrays without hybridization. 14,15 From a scientific point of view, the vertical structure enables the incorporation of complex heterostructure QD layer stacks that can be used to modulate carrier distribution and dynamics for improved detector performance.…”
Intraband quantum dots are degenerately doped semiconductor nanomaterials
that exhibit unique optical properties in mid- to long-wavelength
infrared. To date, these quantum dots have been only studied as lateral
photoconductive devices, while transitioning toward a vertically stacked
structure can open diverse opportunities for investigating advanced
device designs. Here, we report the first vertical intraband quantum
dot heterojunction devices composed of Ag2Se/PbS/Ag2Se quantum dot stacks that bring the advantage of reduced
dark conductivity with a simplified device fabrication procedure.
We discuss the improvement in the colloidal synthesis of Ag2Se quantum dots that are critical for vertical device fabrication,
identify an important process that determines the mid-wavelength infrared
responsivity of the quantum dot film, and analyze the basic device
characteristics and key detector performance parameters. Compared
to the previous generation of Ag2Se quantum dot-based photoconductive
devices, approximately 70 times increase in the mid-wavelength responsivity,
at room temperature, is observed.
“…Recent demonstration of low-cost SWIR and MWIR imaging (Fig. 1c, d) [8, 9] have heightened the interest in this new class of CQD-based FPAs and it is envisioned that the successful implementation of infrared CQD photodetector technology may parallel the broad impact brought by low-cost complementary metal–oxide–semiconductor (CMOS) visible cameras that are ubiquitously used today.Fig. 1CQD-based infrared sensors and imaging FPAs.…”
Colloidal quantum dots provide a powerful materials platform to engineer optoelectronics devices, opening up new opportunities in the thermal infrared spectral regions where no other solution-processed material options exist. This mini-review collates recent research reports that push the technological envelope of colloidal quantum dot-based photodetectors toward mid- and long-wavelength infrared. We survey the synthesis and characterization of various thermal infrared colloidal quantum dots reported to date, discuss the basic theory of device operation, review the fabrication and measurement of photodetectors, and conclude with the future prospect of this emerging technology.
“…This opens new perspectives relative to the use of PbS for low-cost near-and short-wave infrared detection 27,28 and imaging setup. 24,29,30…”
mentioning
confidence: 99%
“…This opens new perspectives relative to the use of PbS for low-cost near-and short-wave infrared detection 27,28 and imaging setup. 24,29,30 ■ DISCUSSION We start by synthesizing PbS nanocrystals with a peak band edge at 920 nm; 31 see Figure 1a. This wavelength is just below the targeted wavelength at 940 nm in order to take into account the red-shift occurring during the ligand exchange procedure needed to build a conductive film.…”
Nanocrystal-based solar cell technologies currently have two materials competing for the highest performances: PbS and perovskites. These latter benefit from a defect-tolerant electronic structure, while PbS benefits from a mature diode fabrication technique and from its near-infrared absorption. Here we choose to revisit the potential of these PbS photodiodes for near-infrared detection and more precisely for active imaging. This mode of detection combines an eye invisible source with a detector. Such detection mode is used for surveillance, industrial sorting, LIDAR, etc. Here we use a state-of-the-art photodiode geometry and we reveal its potential for near-IR active detection at 940 nm. The diode can achieve a high photoresponse of 0.5 A.W -1 , corresponding to an external quantum efficiency of 66% and a detectivity above 10 12 Jones at room temperature. The time response which is often neglected for solar cells is found to be 10 ns for rise time and 1 µs for decay time. We demonstrate that long-distance (over 150 m) and time-gated active imaging can be conducted using this device.
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