Amorphous, Polymorphous, and Microcrystalline Silicon Thin Films Deposited by Plasma at Low Temperatures

High-capacity silicon anodes are attracting more attention, owing to their high theoretical capacities and low working potentials. However, massive volume changes and low intrinsic electric conductivity remain substantial challenges that limit the practical applications of these anodes in lithium-ion batteries (LIBs). In this study, cobalt-doped silicon nanoparticles with different Co concentrations (0.1 %, 0.3 %, and 0.5 %) are prepared by using a simple low-temperature annealing process and are studied as anodes for LIBs. Compared to pure silicon, the obtained 0.5 % cobalt-doped silicon anode can serve as a promising anode and shows a high discharge capacity of 3409 mAh g À 1 (97.2 % capacity retention vs. first reversible capacity) with 98.1 % coulombic efficiency after 40 cycles, at 200 mA g À 1 . After a long 320 cycles, the electrode delivered 3029 mAh g À 1 with 86.4 % capacity retention. This cobalt-doped silicon anode also exhibits superior rate capability and a highly stable long cycle life at higher current densities as well as high mass loading. These remarkable enhancements in electrochemical properties indicate that cobalt doping yields increased conductivity, mitigates volume expansion, and provides shorter lithium transportation lengths across the silicon nanoparticles.

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“…The optical band gap energy was calculated using Tauc's relation [Eq. ]: [49]

true (α h v)^{n} = normalA (h v - E_{normalg})

…”

Section: Resultsmentioning

confidence: 99%

Effect of Cobalt Doping on Enhanced Lithium Storage Performance of Nanosilicon

Nulu

Sohn

2021

ChemElectroChem

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“…It is worth noting that the clear energy separation of the two peak groups is crucial to get separate information about the coating and the underneath films, even at the photon energy (1400 eV) used in this work when compared with High photon energy photoemission (HAXPES) measurements performed at 3, 5, 8 KeV [15]. To single out the a-Si:H film components, we performed a fit of the spectra by the KolXPD code [25]. The baseline of the Si2p is fitted with a set of Voigt doublets with Si2p 3/2 -Si2p 1/2 spin-orbit splitting of 0.6 eV and the gaussian contribution that includes the energy resolution and the disorder.…”

Section: Si2p Core Level Photoemissionmentioning

confidence: 99%

High-Resolution Photoemission Study of Neutron-Induced Defects in Amorphous Hydrogenated Silicon Devices

et al. 2022

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In this paper, by means of high-resolution photoemission, soft X-ray absorption and atomic force microscopy, we investigate, for the first time, the mechanisms of damaging, induced by neutron source, and recovering (after annealing) of p-i-n detector devices based on hydrogenated amorphous silicon (a-Si:H). This investigation will be performed by mean of high-resolution photoemission, soft X-Ray absorption and atomic force microscopy. Due to dangling bonds, the amorphous silicon is a highly defective material. However, by hydrogenation it is possible to reduce the density of the defect by several orders of magnitude, using hydrogenation and this will allow its usage in radiation detector devices. The investigation of the damage induced by exposure to high energy irradiation and its microscopic origin is fundamental since the amount of defects determine the electronic properties of the a-Si:H. The comparison of the spectroscopic results on bare and irradiated samples shows an increased degree of disorder and a strong reduction of the Si-H bonds after irradiation. After annealing we observe a partial recovering of the Si-H bonds, reducing the disorder in the Si (possibly due to the lowering of the radiation-induced dangling bonds). Moreover, effects in the uppermost coating are also observed by spectroscopies.

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“…The fabrication of the C 6 H 11 CH 3 =a-Si:H=Ce:YIG=GCGMZG magnetooptic waveguide can be easily achieved by plasma-enhanced chemical vapor deposition (PECVD). 29,32)…”

Section: Temperature Dependencementioning

confidence: 99%

Temperature-insensitive design of waveguide isolator employing nonreciprocal guided-radiation mode conversion

Choowitsakunlert

Kobashigawa

Hosoya

et al. 2018

Jpn. J. Appl. Phys.

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The temperature dependence of the optical isolator employing a nonreciprocal guided-radiation mode conversion is investigated. The optical isolator consists of a rib-type magnetooptic waveguide with an amorphous Si (a-Si:H) guiding layer. The nonreciprocal phase shift in the optical isolator is calculated at a wavelength of 1.55 µm. The relationship of rib height and rib width for the isolator operation is clarified for various operating temperatures. Refractive indices of layers in the magnetooptic waveguide are considered since proper refractive indices can circumvent waveguide parameter deviation due to the temperature shift. The results show that athermal operation can be achieved by the negative temperature dependence of the refractive index of the upper cladding layer, and the relationship of waveguide parameters varies only slightly with the selected upper cladding layer.

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Amorphous, Polymorphous, and Microcrystalline Silicon Thin Films Deposited by Plasma at Low Temperatures

Cited by 7 publications

References 37 publications

Effect of Cobalt Doping on Enhanced Lithium Storage Performance of Nanosilicon

Effect of Cobalt Doping on Enhanced Lithium Storage Performance of Nanosilicon

High-Resolution Photoemission Study of Neutron-Induced Defects in Amorphous Hydrogenated Silicon Devices

Temperature-insensitive design of waveguide isolator employing nonreciprocal guided-radiation mode conversion

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