Optical properties of mesoporous 4H-SiC prepared by anodic electrochemical etching

Rashid, Marzaini; Horrocks, Ben; Healy, Noel; Goss, Jonathan P.; Horsfall, Alton B.

doi:10.1063/1.4968172

Cited by 13 publications

(9 citation statements)

References 85 publications

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“…Likewise, one possible explanation of the photoluminescence properties of porous SiC is related to the diversity in surface states 21 ; therefore, it is important to know the chemical groups of the internal surface on the porous SiC. It has been demonstrated that the surface of porous SiC contains a wide variety of different chemical groups: carboxylic acid groups, silane groups, hydrocarbon fragments and hydroxyl groups 20,27,28 . Since it is important to understand the underlying physics of luminescence phenomena for its engineering applications, it is critical to carry out a thorough analysis of the carrier recombination mechanisms in porous SiC structures.…”

Section: Introductionmentioning

confidence: 99%

Temperature-dependent photoluminescence properties of porous fluorescent SiC

Tarekegne

et al. 2019

Sci Rep

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A comprehensive study of surface passivation effect on porous fluorescent silicon carbide (SiC) was carried out to elucidate the luminescence properties by temperature dependent photoluminescence (PL) measurement. The porous structures were prepared using an anodic oxidation etching method and passivated by atomic layer deposited (ALD) Al2O3 films. An impressive enhancement of PL intensity was observed in porous SiC with ALD Al2O3, especially at low temperatures. At temperatures below 150 K, two prominent PL emission peaks located at 517 nm and 650 nm were observed. The broad emission peak at 517 nm was attributed to originate from the surface states in the porous structures, which was supported by X-ray photoelectron spectra characterization. The emission peak at 650 nm is due to donor-acceptor-pairs (DAP) recombination via nitrogen donors and boron-related double D-centers in fluorescent SiC substrates. The results of the present work suggest that the ALD Al2O3 films can effectively suppress the non-radiative recombination for the porous structures on fluorescent SiC. In addition, we provide the evidence based on the low-temperature time-resolved PL that the mechanism behind the PL emission in porous structures is mainly related to the transitions via surface states.

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Section: Introductionmentioning

confidence: 99%

Temperature-dependent photoluminescence properties of porous fluorescent SiC

Tarekegne

et al. 2019

Sci Rep

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“…The exact nature of the etched D‐Por‐SiC surface has not yet been ascertained, however previous work indicates that the electrochemically etched SiC surface is likely to show Si depletion and be C‐rich . Here, an amorphous layer approximately 1 nm thickness exists on the etched surface surrounding the pore in D‐Por‐SiC . The chemical composition of this layer is not similar to that of the crystalline face of the bulk crystal.…”

Section: Resultsmentioning

confidence: 97%

“…The formation of an amorphous layer between the crystalline SiC and pore has been reported previously, and the formation of which was linked to the etching conditions. Peaks related to silicon oxycarbide and SiO 2 were observed in XPS spectra and these may be attributed to the existence of an amorphous layer at the surface that influences the oxidation of D‐Por‐SiC.…”

Section: Resultsmentioning

confidence: 99%

“…Mesoporous 4H‐SiC was prepared by anodic electrochemical etching of a n‐type, 8° cut off the c‐ axis ([0001]), 4H‐SiC wafer piece in 48% HF/ethanol (1:1 by volume) for 1 h at an applied bias of 20 V using a Keithley 2611A source meter as described in previous work . The etching time of 1 h at 20 V was sufficiently long to delaminate the porous layer.…”

Section: Methodsmentioning

confidence: 99%

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Pore Wall Thinning of Mesoporous 4H‐SiC by Sacrificial Oxidation

Rashid

Idris

Horrocks

et al. 2018

Crystal Research and Technology

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Pore wall thinning of mesoporous 4H-SiC by sacrificial oxidation is performed. The dimensions within the as-etched porous SiC are reduced during dry oxidation at 1100°C by consuming SiC and removing the grown SiO 2 in the subsequent hydrofluoric acid (HF) dip step. The process reduces the average pore wall thickness from 27 nm to approximately 16 nm and reduces the thickness standard deviation from ±5 to ±1.4 nm for the investigated 9 h oxidation interval. The new pore wall thinning method will enable controlled nanoscale size reduction capability for mesoporous 4H-SiC derived nanostructures.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.

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“…Silicon carbide is a very important semiconductor material [1, 2] which has more than 200 poly-types [3] and has great properties which make it an attractive material to be used for applications in extreme environment [4, 5, 6]. These interesting properties include high strength, high hardness, and low thermal expansion [7, 8, 9], and it has been used in high-temperature applications because of its high thermal conductivity [10, 11, 12] which is 3.6 W/cm-K for 3C–SiC, and 4.9 W/cm-K for 4H–SiC and 6H–SiC [13].…”

Section: Introductionmentioning

confidence: 99%

Crystal structures and the electronic properties of silicon-rich silicon carbide materials by first principle calculations

Alkhaldi

Barman

Huda

2019

Heliyon

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Silicon carbide has been used in a variety of applications including solar cells due to its high stability. The high bandgap of pristine SiC, necessitates nonstoichiometric silicon carbide materials to be considered to tune the band gap for efficient solar light absorptions. In this regards, thermodynamically stable Si-rich SixC1-x materials can be used in solar cell applications without requiring the expensive pure grade silicon or pure grade silicon carbide. In this work, we have used density functional theory (DFT) to examine the stability of various polymorphs of silicon carbide such as 2H–SiC, 4H–SiC, 6H–SiC, 8H–SiC, 10H–SiC, wurtzite, naquite, and diamond structures to produce stable structures of Si-rich SixC1-x. We have systematically replaced the carbon atoms by silicon to lower the band gap and found that the configurations of these excess silicon atoms play a significant role in the stability of Si-rich SixC1-x. Hence, we have investigated different configurations of silicon and carbon atoms in these silicon carbide structures to obtain suitable SixC1-x materials with tailored band gaps. The results indicate that 6H-SixC1-x is thermodynamically the most favorable structure within the scope of this study. In addition, Si substitution for C sites in 6H–SiC enhances the solar absorption, as well as shifts the absorption spectra toward the lower photon energy region. In addition, in the visible range the absorption coefficients are much higher than the pristine SiC.

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Optical properties of mesoporous 4H-SiC prepared by anodic electrochemical etching

Cited by 13 publications

References 85 publications

Temperature-dependent photoluminescence properties of porous fluorescent SiC

Temperature-dependent photoluminescence properties of porous fluorescent SiC

Pore Wall Thinning of Mesoporous 4H‐SiC by Sacrificial Oxidation

Crystal structures and the electronic properties of silicon-rich silicon carbide materials by first principle calculations

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