Photoconductive PbSe thin films and the role of potassium iodide

Harrison, Joel T.; Gupta, Mool C.

doi:10.1016/j.jallcom.2022.164155

Cited by 6 publications

(11 citation statements)

References 10 publications

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“…The surface morphology shows a smoother surface with coalescent grain boundaries, which closely resembles that of the sensitized CBD-grown PbSe film. 6,24,25 Previous studies report that the presence of iodine induces improved surface connectivity and densification by reducing the stress, 24 and we observe similar behavior here. This film morphological resemblance, in addition to the MWIR optical absorption study discussed previously, suggests that the KI ligand exchange approach presented here effectively induces the sensitization required to enable MWIR photoresponsivity.…”

Section: ■ Results and Discussionsupporting

confidence: 87%

“…Finally, in our fully sensitized film, we observe the presence of Pb 3 Se 2 O 6 I 2 phase peaks. 6 This is a distinctive characteristic of the PbSe nanocrystal-derived film that contrasts with former studies that show a formation of a PbI 2 layer on the top of the predeposited PbSe film during the iodization process, 7,24,26 while a recent study has reported the existence of Pb 3 Se 2 O 6 I 2 in the film. 6 The reaction path for the formation of Pb 3 Se 2 O 6 I 2 is shown in eq 3 below: To understand how the electrical properties of the film change after each processing step, Hall effect measurements were conducted at room temperature.…”

Section: ■ Results and Discussionmentioning

confidence: 62%

“…In our approach, the iodine is chemically preincorporated into the PbSe film during the ligand exchange (KI methanol solution) unlike the conventional iodization process, which requires the introduction of iodine gas. 6,7,24 Fourier transform infrared (FTIR) spectroscopy was performed to characterize the MWIR optical absorption of the PbSe film before and after the sensitization (after grain growth and oxidation−iodization annealing). While the asdeposited nanocrystal film shows the absence of MWIR absorption due to the quantum-confined optical gap of PbSe nanocrystallites, an FTIR spectrum obtained from the film after sensitization shows an emergence of an absorbance peak in the MWIR range of 3−5 μm, as shown in Figure 2(b).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The mobility increases further with oxidation−iodization annealing and reaches 9.37 cm 2 /V•s, which is a value comparable to that of the sensitized CBDgrown PbSe film. 24,32 Finally, the electrical resistivity of the PbSe film is shown in Figure 5(c). Our fully sensitized PbSe film exhibits similar dark resistivity values compared to that of the high-performance, uncooled PbSe photodetector reported in the recent study.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Uncooled Mid-Wavelength Infrared Photoconductive Detectors Based on PbSe Nanocrystals

Park

Mahfuz

Huebner

et al. 2023

ACS Appl. Electron. Mater.

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Low-cost, uncooled photodetectors operating in the spectral regions of mid-wavelength infrared (MWIR = 3–5 μm) and long-wavelength infrared (LWIR = 9–12 μm) are anticipated to dominate the future infrared market with its impacts broadly ranging from night driving assist, to drone and microsatellite mounts, to machine vision and augmented goggles. Research interest in lead selenide (PbSe), an 80-year-old technology, has reemerged in recent years, due to its advantageous low manufacturing cost and Auger-suppression properties, as a potential candidate to bridge the current MWIR technology gap. While chemical bath deposition (CBD) and vapor phase deposition (VPD) have been the two major established techniques to fabricate PbSe photoconductive films, they can benefit by adopting the emerging solution-processed fabrication methods to improve the detector manufacturability. In this study, we report on the MWIR photoconductive film derived from colloidal PbSe nanocrystals and demonstrate detectors that reach a specific detectivity of 8 × 108 Jones (200 Hz, 2 V bias) at room temperature. While the sensitization process bears a similarity to the conventional CBD- or VPD-grown PbSe films, the colloidal nanocrystal nature of the starting material requires different processing conditions to reach high responsivity, and those are highlighted in this work. In light of the emergent need for low-cost, uncooled MWIR photodetector technology, the results presented here may serve as a first stepping stone toward future digital additive manufacturing of infrared sensors and imagers.

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Section: ■ Results and Discussionsupporting

confidence: 87%

Section: ■ Results and Discussionmentioning

confidence: 62%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Uncooled Mid-Wavelength Infrared Photoconductive Detectors Based on PbSe Nanocrystals

Park

Mahfuz

Huebner

et al. 2023

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

show abstract

“…Previously, the effect of an iodine dopant on the phase composition, structure, and sensory properties of lead selenide before and after heat treatment in an oxygen-containing atmosphere was studied in ref. 20–26, where PbSe was synthesized in the form of thin polycrystalline layers by both thermal evaporation and CBD. It was found that when introduced into the films iodine stimulates various physicochemical processes in them, which are necessary to provide photosensitive properties and to increase the efficiency of photoluminescence.…”

Section: Introductionmentioning

confidence: 99%