Optical and electrical properties of porous silicon impregnated with Congo Red dye

Chouket, A.; Cherif, B.; Salah, Nasr Ben; Khirouni, K.

doi:10.1063/1.4854555

Cited by 20 publications

(4 citation statements)

References 46 publications

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“…CR readily forms complexes with other materials such as cellulose fibers, the polysaccharide grifolan, poly(vinyl alcohol) hydrogels, graphite oxide, and has been incorporated into polymer films and capsules . Composite materials containing embedded CR molecules are potentially of interest as pH and chemical sensors, hybrid organic‐semiconductor devices, photoresponsive materials, polymer‐electrolyte fuel cells, and nanotheranostics systems …”

Section: Introductionmentioning

confidence: 99%

Insights into the Photophysics and Supramolecular Organization of Congo Red in Solution and the Solid State

et al. 2017

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Steady-state and time-resolved absorption and fluorescence measurements are reported for Congo Red (CR) in aqueous and dimethylsulfoxide (DMSO) solutions. The very low fluorescence quantum yield (≈10 ) for CR in dilute solutions together with the absence of a triplet state indicates that internal conversion is the dominant deactivation route with more than 99.99 % of the quanta loss (attributed to the energy gap law for radiationless transitions). Although no direct evidence for trans-cis photoisomerization was obtained from absorption or fluorescence data, the global analysis of fs-transient absorption data indicates the presence of a photoproduct with a lifetime of ≈170 ps that is suggested to be associated with such a process. Spectral data for more concentrated CR solutions indicate the presence of oblique or twisted J-type aggregates. These results are compared with spectra for CR in the solid state (sodium salt) and intercalated in a layered double hydroxide via a one-step co-precipitation route. Powder XRD and electronic spectral data for the nanohybrid indicate that the CR guest molecules are intercalated as a monolayer consisting of slipped cofacial J-type aggregates.

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Section: Introductionmentioning

confidence: 99%

Insights into the Photophysics and Supramolecular Organization of Congo Red in Solution and the Solid State

et al. 2017

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“…These proportionately large values of the ideality factor may be correlated to the higher density of interface states [25]. It is acknowledged that the presence of two heterojunctions in samples such as the one in the substrate-porous Si interface and the other within the porous Si and Pt is responsible for the enhancement of [26]. In addition, the occurrence of inhomogeneous barrier height can make large as reported earlier [20].…”

Section: Current-voltagementioning

confidence: 70%

Responsivity Dependent Anodization Current Density of Nanoporous Silicon Based MSM Photodetector

Al-Jumaili

Talib

Ramizy

et al. 2016

Journal of Nanomaterials

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Achieving a cheap and ultrafast metal-semiconductor-metal (MSM) photodetector (PD) for very high-speed communications is ever-demanding. We report the influence of anodization current density variation on the response of nanoporous silicon (NPSi) based MSM PD with platinum (Pt) contact electrodes. Such NPSi samples are grown from n-type Si (100) wafer using photoelectrochemical etching with three different anodization current densities. FESEM images of as-prepared samples revealed the existence of discrete pores with spherical and square-like shapes. XRD pattern displayed the growth of nanocrystals with (311) lattice orientation. The nanocrystallite sizes obtained using Scherrer formula are found to be between 20.8 nm and 28.6 nm. The observed rectifying behavior in the I-V characteristics is ascribed to the Pt/PSi/n-Si Schottky barrier formation, where the barrier height at the Pt/PSi interface is estimated to be 0.69 eV. Furthermore, this Pt/PSi/Pt MSM PD achieved maximum responsivity of 0.17 A/W and quantum efficiency as much as 39.3%. The photoresponse of this NPSi based MSM PD demonstrated excellent repeatability, fast response, and enhanced saturation current with increasing anodization current density.

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“…The observed enhancement can also be attributed to the presence of two heterojunctions, substrate-PSi interface and n-PSi-Pt boundary [26]. Moreover, the presence of a heterogeneous barrier height can lead to a higher increase in n compared to the values reported in contemporary studies [27].…”

Section: Photoluminescence Spectroscopymentioning

confidence: 86%

“…The obtained fast response at the optimum anodization chemical ratio (2 : 1 : 1) is possibly due to the defect-free nature, high quality, and considerable photoactive surface area of the synthesized n-PSi. Therefore, it is crucial to note that the rapid response of the photodetector is typically associated with the short transit time of photogenerated carriers that have long lifetimes [14], while the gradual response duration is associated with the incidence of grain margins and increase in surface adsorption of O 2 [26].…”

Section: Photoluminescence Spectroscopymentioning

confidence: 99%

Fabrication of UV Photodetectors Based on Photoelectrochemically Etched Nanoporous Silicon: Effect of Etchants Ratio

Thahe

Qaeed

Abdullah

et al. 2023

Journal of Nanomaterials

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Despite several attempts to enhance the electrical and charge carrier transport characteristics of porous silicon (PSi), the requisite conditions for optimally synthesizing n-PSi with appealing optoelectronic properties are yet to be achieved. Therefore, this research explores the effect of the chemical ratio of precursor materials (HF:C2H6O:H2O2) on the surface morphology, crystalline structure, and optical and electric properties of PSi. The PSi was produced by photoelectrochemical etching followed by anodization of the n-type Si under light illumination. The properties of the as-prepared PSi were studied by means of microscopic and spectroscopic techniques. The HF:C2H6O:H2O2 chemical ratio was optimized at 2 : 1 : 1. A metal–semiconductor–metal (MSM) ultraviolet photodetector (Pt/n-PSi/Pt) was fabricated, which exhibited high performances under UV light (365 nm) illumination. The photodetector was shown to be highly stable and reliable with a rapid rise time of 0.56 s at a bias voltage of +5 V. The MSM photodetector displayed responsivity (Rp) of 9.17 A/m at 365 nm, which significantly exceeds the values reported for TiC/porous Si/Si in some contemporary research. The photodetector fabricated from n-PSi, synthesized at an optimum chemical ratio (2 : 1 : 1) exhibited the best photodetection performance, possibly due to the high porosity and defect-free state of the n-PSi thin films.

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Optical and electrical properties of porous silicon impregnated with Congo Red dye

Abstract: Formation of carbonized porous silicon surfaces by thermal and optically induced reaction with acetylene

Cited by 20 publications

References 46 publications

Insights into the Photophysics and Supramolecular Organization of Congo Red in Solution and the Solid State

Insights into the Photophysics and Supramolecular Organization of Congo Red in Solution and the Solid State

Responsivity Dependent Anodization Current Density of Nanoporous Silicon Based MSM Photodetector

Fabrication of UV Photodetectors Based on Photoelectrochemically Etched Nanoporous Silicon: Effect of Etchants Ratio

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