Growth of Nb2O5 quantum dots by physical vapor deposition

Dhawan, Sahil; Dhawan, Tanuj; Vedeshwar, A. G.

doi:10.1016/j.matlet.2014.03.107

Cited by 14 publications

(8 citation statements)

References 13 publications

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“…The C2 and C3 samples have high E g values when compared to the reference for the orthorhombic phase, and this result may be explained by the particle size. Whenever the size of the particles is smaller than the size of the exciton, the charge carriers become confined within the nanocrystal, which increases the band gap energy due to quantum confinement effect [7,30]. The Bohr exciton radius (a B ) is defined by Equation 3:…”

Section: Resultsmentioning

confidence: 99%

“…where, ε is the dielectric constant of the material, µ * is the reduced mass of electron-hole pair (exciton), m is the electron mass and a 0 is the Bohr radius of the hydrogen atom. Considering that Nb 2 O 5 has reduced effective mass equal to 0.532 [7] and dielectric constant equal to 41 [31], its Bohr exciton diameter is about 8.2 nm. The presence of particles sized around or smaller than this value can explain the variation of the band gap energy for the samples C2 and C3.…”

Section: Resultsmentioning

confidence: 99%

“…However, these properties depend on its structure, morphology and particle size. Nb 2 O 5 can exist in different crystal structures, depending on the method and variables of syntheses [7,8]. The main phases reported are: i) Nb 2 O 5 amorphous at temperatures below 600°C, ii) T-Nb 2 O 5 orthorhombic structure obtained at temperatures between 600 and 900°C and iii) H-Nb 2 O 5 monoclinic structure being the most stable phase occurring at elevated temperatures [9].…”

Section: Introductionmentioning

confidence: 99%

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Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

Marcial

Nakagomi

Angela

et al. 2021

PAC

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The microwave assisted combustion synthesis (MACS) as a new, quick and low cost synthesis method was used for preparation of niobium pentoxide (Nb2O5) powders. The present paper investigated the effect of reactant concentrations (ammonium niobium oxalate, urea and ammonium nitrate) on the characteristics of Nb2O5 nanoparticles. Three samples were synthesized with stoichiometric ratio between the fuel and oxidant (C1), excess of oxidant (C2) and excess of fuel (C3). In all samples, Nb2O5 crystalline nanoparticles with irregular morphology were detected. The synthesis of nanoparticles with smaller diameter in the C2 and C3 samples was confirmed by greater values of band gap energy measured through UV-Visible diffuse reflectance spectroscopy (indicating quantum confinement) and by the Rietveld refinement of X-ray diffraction patterns. The results showed that the amounts of oxidant and fuel can change synthesis temperature, influencing the final characteristics of the particles, such as size and existent phases. In these cases the excess of oxidant and fuel in the C2 and C3 samples, respectively, decreases the average synthesis temperature and decelerates the particle growth and the formation of the monoclinic phase.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

Marcial

Nakagomi

Angela

et al. 2021

PAC

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“…The method primarily involves three most important techniques, i.e., sputtering, pulsed laser deposition (PLD) and thermal evaporation. Effective preparation of crystalline QDs of Nb 2 O 5 (1–20 nm) has been reported using the PVD (Dhawan et al, 2014; Karmakar, 2015). Similar to PVD, CVD method involves chemical reactions that bring about a transformation of the precursor atoms/molecules in the gaseous phase that deposit as a solid film or powder on the substrate.…”

Section: Bottom–up Approachesmentioning

confidence: 99%

Quantum Dot Based Nano-Biosensors for Detection of Circulating Cell Free miRNAs in Lung Carcinogenesis: From Biology to Clinical Translation

et al. 2018

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Lung cancer is the most frequently occurring malignancy and the leading cause of cancer-related death for men in our country. The only recommended screening method is clinic based low-dose computed tomography (also called a low-dose CT scan, or LDCT). However, the effect of LDCT on overall mortality observed in lung cancer patients is not statistically significant. Over-diagnosis, excessive cost, risks associated with radiation exposure, false positive results and delay in the commencement of the treatment procedure questions the use of LDCT as a reliable technique for population-based screening. Therefore, identification of minimal-invasive biomarkers able to detect malignancies at an early stage might be useful to reduce the disease burden. Circulating nucleic acids are emerging as important source of information for several chronic pathologies including lung cancer. Of these, circulating cell free miRNAs are reported to be closely associated with the clinical outcome of lung cancer patients. Smaller size, sequence homology between species, low concentration and stability are some of the major challenges involved in characterization and specific detection of miRNAs. To circumvent these problems, synthesis of a quantum dot based nano-biosensor might assist in sensitive, specific and cost-effective detection of differentially regulated miRNAs. The wide excitation and narrow emission spectra of these nanoparticles result in excellent fluorescent quantum yields with a broader color spectrum which make them ideal bio-entities for fluorescence resonance energy transfer (FRET) based detection for sequential or simultaneous study of multiple targets. In addition, photo-resistance and higher stability of these nanoparticles allows extensive exposure and offer state-of-the art sensitivity for miRNA targeting. A major obstacle for integrating QDs into clinical application is the QD-associated toxicity. However, the use of non-toxic shells along with surface modification not only overcomes the toxicity issues, but also increases the ability of QDs to quickly detect circulating cell free miRNAs in a non-invasive mode. The present review illustrates the importance of circulating miRNAs in lung cancer diagnosis and highlights the translational prospects of developing QD-based nano-biosensor for rapid early disease detection.

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“…Диаметр синтезируемых частиц определяется скоростью осаждения. Порошки оксидов цинка размером от 20 до 40 нм были получены в реакторе c применением солнечных печей для синтеза методом solar physical vapor deposition SPVD [10,11]. Кристаллическая фаза формируется только после следующей за осаждением термической обработки (700 о С).…”

Section: Introductionunclassified

Oxide Iron-Material Synthesized on a Solar Furnace

Payzyllakhanov¹,

Shermatov²,

Rajamatov³

et al. 2019

JSID

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ҚУЁШ САНДОНИДА СИНТЕЗ ҚИЛИНГАН, ОКСИДЛИ ТЕМИРБАРИЙЛИ МАТЕРИАЛ Пайзуллаханов Мухаммаде-Султанхан Саидивалиханович ф.-м.ф.н. лаборатория мудири; Шерматов Жавоҳир Зафарович кичик илмий ходим; Ражаматов Отабек Тулаббоевич кичик илмий ходим; Нодирматов Эркин Зокирматович кичик илмий ходим ЎзР ФА «Физика-Қуёш» ИИЧБ Материалшунослик институти Аннотация. Ишқорий ер металлари ферритлари асосидаги магнит материаллар юқори солиштирма электрик қаршилик (104-107 Ом) ва юқори коэрцитив куч (500 кА/м) намоён этади. Бунда магнитланиш тўйинувчанлиги қиймати доменлар (кристаллитлар) ўлчамларига кучли боғлиқ. Шаклланаётган материал микроструктураси ҳамда кристаллитлар ўлчамлари технологик шартларга боғлиқ бўлади. Шунинг учун материал микроструктураси (кристаллитлар ўлчамлари)ни бошқариш орқали материалнинг магнит хоссаларини бошқариш мумкин. Бу эса магнит материалларни эритмадан синтез қилиш жараёнларини тадқиқ этишнинг фундаментал ва амалий долзарблигини белгилайди. Ушбу ишнинг мақсади магнит материаллар -барий, стронций ва висмут ферритларини Катта қуёш печида эритиш орқали синтез қилиш жараёнларини ўрганишдан иборат. Ишда рентгеноструктуравий таҳлил, микроскопия ҳамда материалларнинг физик параметрларини ўлчаш усуллари қўлланилди. Қуёш сандонида синтез қилинган, феррит барий ўрганилган. Мақолада BaСО 3 + Fe 2 O 3 қоришмаси юқори мужассамланган қуёш нурлари (350Вт/см 2 ) таъсирида, гексагонал феррит барий 4(Fe 2 O 3 )4(FeO)BaFeO 3 -X, кубик Ba 3 Fe 2 O 6 -X= 2(BaО)FeОВаFeO 3 -X ва тетрагонал BaOFeOBaFeO 3 -X модификацияси ҳосил бўлганлиги кўрсатилган. Технологик жараёнини модификациялаш орқали зарур хоссалар (солиштирма электр қаршилиги 1010 Ом·cм, зичлиги 5 г/см 3 , магнитодиэлектрик эффекти 4,1%) намоён этувчи магнит материаллар олиш мумкин. Бундай материаллар электрон схемаларда частота ва ток кучланиш амплитудаларини стабиллаш учун қўлланиши мумкин. Таянч тушунчалар. магнит материал, қуёш сандони, структура деффектлари, диэлектрик ўтказувчанлик. ОКСИДНЫЙ ЖЕЛЕЗИСТОБАРИЕВЫЙ МАТЕРИАЛ, СИНТЕЗИРОВАННЫЙ НА СОЛНЕЧНОЙ ПЕЧИ Пайзуллаханов Мухаммаде-Султанхан Саидивалиханович к.ф.-м.н., заведующий лабораторией; Шерматов Жавохир Зафарович младший научный сотрудник; Ражаматов Отабек Тулаббоевич младший научный сотрудник; Нодирматов Эркин Зокирматович младший научный сотрудник Институт материаловедения НПО «Физика-Солнце» АН РУз ТЕХНИЧЕСКИЕ НАУКИ Илм-фан ва инновацион ривожланиш / 2019 №3 58 Аннотация. Магнитные материалы на основе ферритов щелечноземельных элементов имеют высокое удельное электрическое сопротивление (104-107 Ом) и высокую коэрцитивную силу (500 кА/м). При этом значения намагниченности насыщения сильно зависят от размера доменов (кристаллитов). Микроструктура, а также размер кристаллитов структурируемого материала зависит от технологических условий синтеза. Поэтому управляя микроструктурой (размерами кристаллитов) материала, можно добиться варьирования магнитных свойств материала, тем самым исследование процессов синтеза магнитных материалов из расплава представляется актуальным как в фундаментальном, так и прикладном аспе...

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Growth of Nb2O5 quantum dots by physical vapor deposition

Cited by 14 publications

References 13 publications

Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

Quantum Dot Based Nano-Biosensors for Detection of Circulating Cell Free miRNAs in Lung Carcinogenesis: From Biology to Clinical Translation

Oxide Iron-Material Synthesized on a Solar Furnace

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