Optoelectronic properties of semiconductor nanowires

Pan, Anlian; Zhu, Xiaoli

doi:10.1016/b978-1-78242-253-2.00012-8

Cited by 20 publications

(15 citation statements)

References 119 publications

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“…Cadmium sulfide (CdS) is an important II–VI semiconductor characterized by excellent thermal and chemical stability and strong optical absorption. It is widely used for the production of solar cells, photodetectors, light emitting diodes, and lasers and for the synthesis of a variety of nanostructures and quantum dots. , However, its primary use is as a pigment, widely employed in the paint, plastic, textile, ceramics, and glass industries.…”

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confidence: 99%

Degradation of Cadmium Yellow Paint: New Evidence from Photoluminescence Studies of Trap States in Picasso’s Femme (Époque des “Demoiselles d’Avignon”)

et al. 2019

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Paints based on cadmium sulfide (CdS) were popular among artists beginning in the mid-19th century. Some paint formulations are prone to degrade, discoloring and disfiguring paintings where they have been used. Pablo Picasso's Femme (E ́poque des "Demoiselles d'Avignon") (1907) includes two commercial formulations of CdS: one is visibly degraded and now appears brownish yellow, while the other appears relatively intact and is vibrant yellow. This observation inspired the study reported here of the photoluminescence emission from trap states of the two CdS paints, complemented by data from multispectral imaging, Xray fluorescence spectroscopy, micro-FTIR, and SEM-EDS. The two paints exhibit trap state emissions that differ in terms of spectrum, intensity, and decay kinetics. In the now-brownish yellow paint, trap state emission is highly favored with respect to near band edge optical recombination. This observation suggests a higher density of surface defects in the now-brownish yellow paint that promotes the surface reactivity of CdS particles and their subsequent paint degradation. CdS is a semiconductor, and surface defects in semiconductors can trap free charge carriers; this interaction becomes stronger at reduced particle size or, equivalently, with increased surface to volume ratio. Here, we speculate that the strong trap state emission in the now-brownish cadmium yellow paint is linked to the presence of CdS particles with a nanocrystalline phase, possibly resulting from a low degree of calcination during pigment synthesis. Taken together, the results presented here demonstrate how photoluminescence studies can probe surface defects in CdS paints and lead to an improved understanding of their complex degradation mechanisms.

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confidence: 99%

Degradation of Cadmium Yellow Paint: New Evidence from Photoluminescence Studies of Trap States in Picasso’s Femme (Époque des “Demoiselles d’Avignon”)

et al. 2019

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“…The dark current from the detector on SiO 2 substrate is 8.83 × 10 −6 mA at 70 V bias voltage. To consider the photocurrent and dark current in the overall performance of the detectors, the photosensitivity of the detectors was calculated using the following formula:

where

is the photocurrent when the detector is under illumination and

is the dark current when the detector is under darkness [ 29 ]. The calculation results for a bias voltage of 70 V are summarized in Table 1 .…”

Section: Resultsmentioning

confidence: 99%

“…The detector on Si substrate exhibited a faster response time compared with those on SiO 2 and SLG substrates, while it was comparable to the response time of the diamond sensor. The smaller crystallite sizes on the film on Si contribute to more crystallite boundaries and therefore a shorter carrier lifetime as the mean free path of the moving carriers would also be shorter [ 29 ]. As a result, the photocurrent decays faster, resulting in a faster response speed.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Substrate and Thickness on the Photoconductivity of Nanoparticle Titanium Dioxide Thin Film Vacuum Ultraviolet Photoconductive Detector

et al. 2021

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Vacuum ultraviolet radiation (VUV, from 100 nm to 200 nm wavelength) is indispensable in many applications, but its detection is still challenging. We report the development of a VUV photoconductive detector, based on titanium dioxide (TiO2) nanoparticle thin films. The effect of crystallinity, optical quality, and crystallite size due to film thickness (80 nm, 500 nm, 1000 nm) and type of substrate (silicon Si, quartz SiO2, soda lime glass SLG) was investigated to explore ways of enhancing the photoconductivity of the detector. The TiO2 film deposited on SiO2 substrate with a film thickness of 80 nm exhibited the best photoconductivity, with a photocurrent of 5.35 milli-Amperes and a photosensitivity of 99.99% for a bias voltage of 70 V. The wavelength response of the detector can be adjusted by changing the thickness of the film as the cut-off shifts to a longer wavelength, as the film becomes thicker. The response time of the TiO2 detector is about 5.8 μs and is comparable to the 5.4 μs response time of a diamond UV sensor. The development of the TiO2 nanoparticle thin film detector is expected to contribute to the enhancement of the use of VUV radiation in an increasing number of important technological and scientific applications.

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“…Since photoconductivity is dependent on the number of the photogenerated electron−hole pairs and the mobility of the carriers, 95 the larger efficiency of [Ni(Ar-edt) 2 ] metal bis(1,2dithiolene) complexes with respect to those reported in the past, 39−43 as well as the differences between 1 and 2, can be tentatively attributed to the their different solid-state structures, given the extreme sensitivity of the solid-state electronic properties of molecular materials to minute changes of the molecular shapes and intermolecular interactions. Future studies will be directed at addressing these aspects.…”

Section: ■ Conclusionmentioning

confidence: 99%

Photoconducting Devices with Response in the Visible–Near-Infrared Region Based on Neutral Ni Complexes of Aryl-1,2-dithiolene Ligands

et al. 2020

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Metal Bis(1,2-dithiolene) complexes belonging to the class [Ni(Ar-edt) 2 ] x-[Ar-edt 2-= arylethylene-1,2-dithiolate; Ar = phenyl, ( 1x-), 2-naphthyl (2 x-); x = 0, 1] were fully characterized by NMR, UV-Vis-NIR, diffuse reflectance, and FT-IR spectroscopy, as well as cyclic voltammetry, and single crystal X-ray diffraction analysis. These complexes have emerged as new photoconducting materials that allowed for the development of a prototype of photodetectors with response in the Vis-NIR region. The photodetecting devices showed in some cases quantum efficiencies with orders of magnitude higher than those of previously reported 1,2-dithiolene systems.

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Optoelectronic properties of semiconductor nanowires

Cited by 20 publications

References 119 publications

Degradation of Cadmium Yellow Paint: New Evidence from Photoluminescence Studies of Trap States in Picasso’s Femme (Époque des “Demoiselles d’Avignon”)

Degradation of Cadmium Yellow Paint: New Evidence from Photoluminescence Studies of Trap States in Picasso’s Femme (Époque des “Demoiselles d’Avignon”)

Effect of Substrate and Thickness on the Photoconductivity of Nanoparticle Titanium Dioxide Thin Film Vacuum Ultraviolet Photoconductive Detector

Photoconducting Devices with Response in the Visible–Near-Infrared Region Based on Neutral Ni Complexes of Aryl-1,2-dithiolene Ligands

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