Micro-Raman Scattering of Nanoscale Silicon in Amorphous and Porous Silicon

Periasamy, Sangeetha; Venkidusamy, Sasirekha; Venkatesan, Ragavendran; Mayandi, J.; Pearce, Joshua M.; Selj, Josefine; Ramakrishnan, V.

doi:10.1515/zpch-2016-0961

Cited by 21 publications

(26 citation statements)

References 32 publications

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“…Typically, a sharp peak is observed at ∼520 cm −1 corresponding to crystalline Si and a broad peak centered around ∼480 cm −1 for amorphous Si. 35 For nanocrystalline Si, as the crystallite size and degree of crystallinity decrease, the peak shifts from 520 cm −1 to lower wavenumbers and the full width at half maximum (FWHM) of the peak increases. 36 While the powder XRD patterns of all the mp-Si NPs were similar, the Raman analysis revealed the differences in these samples (Fig.…”

Section: Resultsmentioning

confidence: 99%

Photocatalytic hydrogen generation using mesoporous silicon nanoparticles: influence of magnesiothermic reduction conditions and nanoparticle aging on the catalytic activity

2021

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Section: Resultsmentioning

confidence: 99%

Photocatalytic hydrogen generation using mesoporous silicon nanoparticles: influence of magnesiothermic reduction conditions and nanoparticle aging on the catalytic activity

2021

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“…Therefore, the Raman result confirms that no crystallization was observed on the HBP after heat treatment. For the USi_HBP and HSi_HBP electrodes, three characteristic broad peaks centered at 481 and 795 cm −1 were assigned to amorphous Si [ 31 , 32 , 33 , 34 ], whereas the D and G-bands of the CNT disappeared, indicating that the surface of the carbon electrode was covered by amorphous Si [ 34 ]. The Raman spectrum showed that the Si was still in the amorphous state, and a crystalline Si peak did not appear.…”

Section: Resultsmentioning

confidence: 99%

High Electrochemical Performance Silicon Thin-Film Free-Standing Electrodes Based on Buckypaper for Flexible Lithium-Ion Batteries

et al. 2021

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Recently, applications for lithium-ion batteries (LIBs) have expanded to include electric vehicles and electric energy storage systems, extending beyond power sources for portable electronic devices. The power sources of these flexible electronic devices require the creation of thin, light, and flexible power supply devices such as flexile electrolytes/insulators, electrode materials, current collectors, and batteries that play an important role in packaging. Demand will require the progress of modern electrode materials with high capacity, rate capability, cycle stability, electrical conductivity, and mechanical flexibility for the time to come. The integration of high electrical conductivity and flexible buckypaper (oxidized Multi-walled carbon nanotubes (MWCNTs) film) and high theoretical capacity silicon materials are effective for obtaining superior high-energy-density and flexible electrode materials. Therefore, this study focuses on improving the high-capacity, capability-cycling stability of the thin-film Si buckypaper free-standing electrodes for lightweight and flexible energy-supply devices. First, buckypaper (oxidized MWCNTs) was prepared by assembling a free stand-alone electrode, and electrical conductivity tests confirmed that the buckypaper has sufficient electrical conductivity (10−4(S m−1) in LIBs) to operate simultaneously with a current collector. Subsequently, silicon was deposited on the buckypaper via magnetron sputtering. Next, the thin-film Si buckypaper freestanding electrodes were heat-treated at 600 °C in a vacuum, which improved their electrochemical performance significantly. Electrochemical results demonstrated that the electrode capacity can be increased by 27/26 and 95/93 μAh in unheated and heated buckypaper current collectors, respectively. The measured discharge/charge capacities of the USi_HBP electrode were 108/106 μAh after 100 cycles, corresponding to a Coulombic efficiency of 98.1%, whereas the HSi_HBP electrode indicated a discharge/charge capacity of 193/192 μAh at the 100th cycle, corresponding to a capacity retention of 99.5%. In particular, the HSi_HBP electrode can decrease the capacity by less than 1.5% compared with the value of the first cycle after 100 cycles, demonstrating excellent electrochemical stability.

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“…Сдвиг и появившуюся асимметрию главного пика мы связываем с возникновением нанокристалитов в этой области. Рассчитать размер нанокристаллитов можно по сдвигу ω фононной моды кремния [18]:…”

Section: результаты и обсужденияunclassified

“…Если происходит разупорядочение решетки, то полуширины полос КРС увеличиваются [11,12]. При уменьшении размеров кристаллов до размеров ∼ 2−10 nm происходит нарушение правил отбора по волновому вектору, и максимум полосы КРС смещается в сторону низких частот, а сама полоса становится асимметричной: появляется низкочастотное крыло основного колебания [13,14]. Из такого спектра по форме и положению линии КРС в области 520 cm −1 , отвечающей за колебания Si-Si, можно оценить размер нанокристаллов.…”

Section: Introductionunclassified

Индуцируемые Напряжения, Возникающие В Кристаллическом Кремнии При Воздействии Ультракоротких Лазерных Импульсов Различной Длительности В Воздухе И Воде

Смирнов¹,

Кудряшов²,

Мельник³

et al. 2021

Оптика И Спектроскопия

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Производилась модификация поверхности кремния в одноимпульсном режиме фемто-пикосекундными лазерными импульсами (0.3 и 10 ps) ближнего ИК диапазона (1030 nm) при абляции в воздухе и воде. Полученные структуры изучались с помощью микроскопии комбинационного рассеяния света. В ходе исследования установлено, что на границе кратера появляются нанокристаллиты размером 7-8 nm. Обнаружены локальные механические напряжения в центре кратера, знак которых зависит от приложенной плотности энергии. Наибольшие локальные сжимающие напряжения возникают в воде в субфиламентационном режиме при максимальных плотностях энергии. Ключевые слова: кремний, спектроскопия комбинационного рассеяния света, ультракороткие импульсы, одноимпульсная абляция в воздухе и в жидкости, локальные напряжения.

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Micro-Raman Scattering of Nanoscale Silicon in Amorphous and Porous Silicon

Cited by 21 publications

References 32 publications

Photocatalytic hydrogen generation using mesoporous silicon nanoparticles: influence of magnesiothermic reduction conditions and nanoparticle aging on the catalytic activity

Photocatalytic hydrogen generation using mesoporous silicon nanoparticles: influence of magnesiothermic reduction conditions and nanoparticle aging on the catalytic activity

High Electrochemical Performance Silicon Thin-Film Free-Standing Electrodes Based on Buckypaper for Flexible Lithium-Ion Batteries

Индуцируемые Напряжения, Возникающие В Кристаллическом Кремнии При Воздействии Ультракоротких Лазерных Импульсов Различной Длительности В Воздухе И Воде

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