Готові списки джерел за темами / Type II Heterostructures

Добірка наукової літератури з теми "Type II Heterostructures"

Автор: Grafiati
Опубліковано: 7 вересня 2023

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями

Оберіть тип джерела:

Зміст

Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Type II Heterostructures".

Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.

Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.

Статті в журналах з теми "Type II Heterostructures"

1

Maevskaya, Maria V., Aida V. Rudakova, Alexandra V. Koroleva, Aleksandr S. Sakhatskii, Alexei V. Emeline, and Detlef W. Bahnemann. "Effect of the Type of Heterostructures on Photostimulated Alteration of the Surface Hydrophilicity: TiO2/BiVO4 vs. ZnO/BiVO4 Planar Heterostructured Coatings." Catalysts 11, no. 12 (November 23, 2021): 1424. http://dx.doi.org/10.3390/catal11121424.

Повний текст джерела
Анотація:
Here, we report the results of comparative studies of the photostimulated hydrophilic behavior of heterostructured TiO2/BiVO4 and ZnO/BiVO4, and monocomponent TiO2 and ZnO nanocoating surfaces. The chemical composition and morphology of the synthesized nanocoatings were characterized by XPS, SEM, and AFM methods. The electronic energy structure of the heterostructure components (band gap, top of the valence band, bottom of the conduction band, and Fermi level position) was determined on the basis of experimental results obtained by XPS, UV-V absorption spectroscopy and Kelvin probe methods. According to their electronic energy structure, the ZnO/BiVO4 and TiO2/BiVO4 heterostructures correspond to type I and type II heterostructures, respectively. The difference in the type of heterostructures causes the difference in the charge transfer behavior at heterojunctions: the type II TiO2/BiVO4 heterostructure favors and the type I ZnO/BiVO4 heterostructure prevents the photogenerated hole transfer from BiVO4 to the outer layer of the corresponding metal oxide. The results of the comparative studies show that the interaction of the photogenerated holes with surface hydroxy-hydrated multilayers is responsible for the superhydrophilic surface conversion accompanying the increase of the surface free energy and work function. The formation of the type II heterostructure leads to the spectral sensitization of the photostimulated surface superhydrophilic conversion.
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Bhardwaj, Garima, Sandhya K., Richa Dolia, M. Abu-Samak, Shalendra Kumar, and P. A. Alvi. "A Comparative Study on Optical Characteristics of InGaAsP QW Heterostructures of Type-I and Type-II Band Alignments." Bulletin of Electrical Engineering and Informatics 7, no. 1 (March 1, 2018): 35–41. http://dx.doi.org/10.11591/eei.v7i1.872.

Повний текст джерела
Анотація:
In this paper, we have configured InGaAsP QW (quantum well) heterostructures of type-I and type-II band alignments and simulated their optical characteristics by solving 6 x 6 Kohn-Luttinger Hamiltonian Matrix. According to the simulation results, the InGaAsP QW heterostructure of type-I band alignment has been found to show peak optical gain (TE mode) of the order of~3600/cm at the transition wavelength~1.40 µm; while of type-II band alignment has achieved the peak gain (TE mode) of the order of~7800/cm at the wavelength of~1.85 µm (eye safe region). Thus, both of the heterostructures can be utilized in designing of opto-or photonic devices for the emission of radiations in NIR (near infrared region) but form the high gain point of view, the InGaAsP of type-II band alignment can be more preferred.
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Behara, Dilip Kumar, Jalajakshi Tammineni, and Mukkara Sudha Maheswari. "TiO2/ZnO: Type-II Heterostructures for electrochemical crystal violet dye degradation studies." Macedonian Journal of Chemistry and Chemical Engineering 39, no. 2 (October 26, 2020): 217. http://dx.doi.org/10.20450/mjcce.2020.2058.

Повний текст джерела
Анотація:
Semiconductor nanomaterials with proper band edge alignments forming “heterostructure” assemblies have significant importance in water splitting, dye degradation, and other electrochemical studies. The formed heterojunction between material phases facilitates fast charge carrier transport and, thereby, improves electrochemical performance in associated processes. Herein, we report a type-II heterostructure combining TiO2 and ZnO nanomaterials for electrochemical crystal violet dye degradation studies. The rationale in choosing the above materials (TiO2, ZnO) in the present study includes stability, lack of toxicity, and high oxidation power, but they also facilitate fast charge carrier movements due to proper band edge alignments, forming a type-II heterostructure assembly. Cyclic voltammetry, combined with ultraviolet-visible analysis, was used to identify the cathodic and anodic peak currents and trace the exact mechanism of dye degradation. The electro-catalytic performance of TiO2/ZnO heterostructured materials fabricated on titania (Ti) substrate show higher performance, in comparison to all individual material interfaces, due to synergistic interaction and synchronized charge transport.
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Li, Jiayi, Yanming Lin, Minjie Zhang, Ying Peng, Xinru Wei, Zhengkun Wang, Zhenyi Jiang та Aijun Du. "Ferroelectric polarization and interface engineering coupling of Z-scheme ZnIn2S4/α-In2Se3 heterostructure for efficient photocatalytic water splitting". Journal of Applied Physics 133, № 10 (14 березня 2023): 105702. http://dx.doi.org/10.1063/5.0136862.

Повний текст джерела
Анотація:
It is of great significance to design an efficient heterostructure for photocatalytic hydrogen production to solve the energy shortage and environmental crisis. In this letter, we investigate the structure, electron of interface, optical, charge transfer, and photocatalytic mechanism of three different ZnIn2S4/α-In2Se3 heterostructures by hybrid density functional calculation. It is interesting that the presence of an external electric field not only can change the bandgap but also can modulate the band alignment type. Among them, heterostructure A belongs to type II heterostructure, and heterostructure B and C belong to a Z-scheme heterostructure. Especially in heterostructure C, the electrons deposited on CBM of a ZnIn2S4 monolayer will play an important role in the hydrogen production process. Meanwhile, the small bandgap of ZnIn2S4/α-In2Se3 Z-scheme heterostructures enables it to obtain a wide light absorption range. Therefore, this study contributes to the design of a novel and potential Z-scheme heterostructure photocatalyst with broad application prospects in both electronic and optoelectronic fields.
Стилі APA, Harvard, Vancouver, ISO та ін.
5

Zakharova, A., and V. Gergel. "Resonant tunneling in type II heterostructures." Solid State Communications 96, no. 4 (October 1995): 209–13. http://dx.doi.org/10.1016/0038-1098(95)00435-1.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Schäfer, F., M. Stein, J. Lorenz, F. Dobener, C. Ngo, J. T. Steiner, C. Fuchs, et al. "Gain recovery dynamics in active type-II semiconductor heterostructures." Applied Physics Letters 122, no. 8 (February 20, 2023): 082104. http://dx.doi.org/10.1063/5.0128777.

Повний текст джерела
Анотація:
Type-II heterostructures as active layers for semiconductor laser devices combine the advantages of a spectrally broad, temperature stable, and efficient gain with the potential for electrical injection pumping. Their intrinsic charge carrier relaxation dynamics limit the maximum achievable repetition rates beyond any constraints of cavity design or heat dissipation. Of particular interest are the initial build up of gain after high-energy injection and the gain recovery dynamics following depletion through a stimulated emission process. The latter simulates the operation condition of a pulsed laser or semiconductor optical amplifier. An optical pump pulse injects hot charge carriers that eventually build up broad spectral gain in a model (Ga,In)As/GaAs/Ga(As,Sb) heterostructure. The surplus energies of the optical pump mimic the electron energies typical for electrical injection. Subsequently, a second laser pulse tuned to the broad spectral gain region depletes the population inversion through stimulated emission. The spectrally resolved nonlinear transmission dynamics reveal gain recovery times as fast as 5 ps. These data define the intrinsic limit for the highest laser repetition rate possible with this material system in the range of 100 GHz. The experimental results are analyzed using a microscopic many-body theory identifying the origins of the broad gain spectrum.
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Li, Honglin, Yuting Cui, Haijun Luo, and Wanjun Li. "The strain induced type-II band re-alignment of blue phosphorus-GeX (X = C/H/Se) heterostructures." European Physical Journal Applied Physics 89, no. 1 (January 2020): 10103. http://dx.doi.org/10.1051/epjap/2020190325.

Повний текст джерела
Анотація:
Efforts to efficiently use of the next generation 2-dimension (2D) structured monolayers is getting a lot of attention for their excellent properties recently. In this work, we composite the blue phosphorus (BP) and monolayer GeX (X = C/H/Se) via van der Waals force (vdW) interaction to obtain well defined type-II band alignment heterostructures. A systematic theoretic study is conducted to explore the interlayer coupling effects and the bands re-alignment of BP-GeX (X = C/H/Se) heterostructure after the strain imposed. To devise usable and efficient materials to degrade pollutant or used as a potential photovoltaic cell material, previous researches have proved that using 2D materials as components is a feasible way to obtain high performance. Here, we prudently present a comprehensive investigation on the BP and GeX (X = C/H/Se) with different twisted angles via first-principles calculation to lay a theoretical framework on the band alignment and carriers' separation. It reveals that the intrinsic electronic properties of BP and GeX are roughly preserved in the corresponding heterostructures. Upon strain applied, band alignment can be flexibly manipulated by varying external imposed strain. The heterostructures can maintain type-II character within a certain strain range, and thus the carriers are spatially separated to different portions. This work not only provides a deep insight into the construction of the heterostructure, but presents a new possibility to search for a flexible and feasible approach to promote its catalytic performance. The corresponding results would provide meaningful guidelines for designing 2D structure based novel materials.
Стилі APA, Harvard, Vancouver, ISO та ін.
8

Ichimura, Masaya. "Calculation of Band Offsets of Mg(OH)2-Based Heterostructures." Electronic Materials 2, no. 3 (July 1, 2021): 274–83. http://dx.doi.org/10.3390/electronicmat2030019.

Повний текст джерела
Анотація:
The band alignment of Mg(OH)2-based heterostructures is investigated based on first-principles calculation. (111)-MgO/(0001)-Mg(OH)2 and (0001)-wurtzite ZnO/(0001)-Mg(OH)2 heterostructures are considered. The O 2s level energy is obtained for each O atom in the heterostructure supercell, and the band edge energies are evaluated following the procedure of the core-level spectroscopy. The calculation is based on the generalized gradient approximation with the on-site Coulomb interaction parameter U considered for Zn. For MgO/Mg(OH)2, the band alignment is of type II, and the valence band edge of MgO is higher by 1.6 eV than that of Mg(OH)2. For ZnO/Mg(OH)2, the band alignment is of type I, and the valence band edge of ZnO is higher by 0.5 eV than that of Mg(OH)2. Assuming the transitivity rule, it is expected that Mg(OH)2 can be used for certain types of heterostructure solar cells and dye-sensitized solar cells to improve the performance.
Стилі APA, Harvard, Vancouver, ISO та ін.
9

Баженов, Н. Л., К. Д. Мынбаев, А. А. Семакова та Г. Г. Зегря. "Сравнительный анализ эффективности электролюминесценции в гетероструктурах I и II типа на основе узкозонных соединений А-=SUP=-III-=/SUP=-B-=SUP=-V-=/SUP=-". Физика и техника полупроводников 56, № 5 (2022): 477. http://dx.doi.org/10.21883/ftp.2022.05.52349.9805.

Повний текст джерела
Анотація:
A detailed analysis of the mechanisms of radiative and Auger recombination in type I and II heterostructures based on narrow-gap AIIIBV materials is presented. It is shown that the presence of a heterointerface fundamentally changes the nature of these recombination processes differently, depending on the type of heterojunction. Results of our study of the electroluminescence of type I and II LED heterostructures based on InAs(Sb)/InAsSbP quantum wells are presented. It is shown that the increase in relative efficiency of radiative recombination in type II heterostructures due to suppression of Auger recombination contributes to generation of stimulated emission in these heterostructures at low temperatures (4.2−70K).
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Liu, Zixiang, and Zhiguo Wang. "Electronic Properties of MTe2/AsI3(M=Mo and W) Van der Waals Heterostructures." MATEC Web of Conferences 380 (2023): 01011. http://dx.doi.org/10.1051/matecconf/202338001011.

Повний текст джерела
Анотація:
Two dimensional (2D) materials with unique physical or chemical prperties has triggered worldwide interest in the fields of material science, condensed matter physics, and devices physics. Vertically stacking different 2D materials enables the creation of a large variety of van der Waals heterostructures. The van der Waals heterostructures robust the merits of the 2D materials electronic prperties. Using density functional theory calculations, the electronic structure of MTe2/AsI3(M=Mo and W) Van der Waals heterostructures are investigated in this work. The results show by stacking MTe2(M=Mo and W) and AsI3 vertically, a strongly binding vdW heterostructure with a type-II band alignment can be formed, which gives expectation of high multifunctional electronic performance. This theoretical study provides vital insights of 2D materials and their heterostructures which could be potential candidates for future nanoelectronic applications.
Стилі APA, Harvard, Vancouver, ISO та ін.
Більше джерел

Дисертації з теми "Type II Heterostructures"

1

LUGAGNE-DELPON, EMMANUEL. "Contributions a l'etude des heterostructures de type ii inp-(alin)as." Paris 6, 1993. http://www.theses.fr/1993PA066160.

Повний текст джерела
Анотація:
Lorsqu'ils sont associes, les materiaux inp et (al#0#. #4#8in#0#. #5#2)as forment une heterostructure de type ii, puisque les electrons sont confines dans inp et les trous dans l'alliage ternaire. Bien que les recombinaisons radiatives proviennent uniquement du recouvrement des parties evanescentes des fonctions d'ondes, ce systeme offre d'excellentes proprietes optiques: un grand rendement radiatif, dans une gamme de longueur d'onde aisement accessible a l'experimentateur (autour de 1 m). En particulier, ce rendement radiatif a permis d'observer une emission laser dans un superreseau, sous un pompage optique de puissance raisonnable. Grace a l'etude detaillee d'interfaces simples et de superreseaux inp-(alin)as crus par mo-cvd, il est montre experimentalement: d'une part, que les offsets inp-(alin)as et (alin)as-inp different de 100 mev; d'autre part, que dans la trilogie inp-(alin)as-(inga)as, la loi de transitivite sur les offsets de valence moyens est violee de plus de 100 mev. Enfin une etude preliminaire des effets electrooptiques dans les superreseaux est presentee
Стилі APA, Harvard, Vancouver, ISO та ін.
2

TEISSIER, ROLAND. "Effets electro-optiques dans les heterostructures gaas/alas de type ii." Paris 6, 1992. http://www.theses.fr/1992PA066340.

Повний текст джерела
Анотація:
Les superreseaux gaas/alas presentent un alignement de bandes de type ii, lorsque l'etat fondamental de conduction est issu des vallees x situees en bord de zone de brillouin. Les electrons photocrees sont alors confines dans les couches d'alas et les trous dans les couches de gaas. L'objet de ce travail est l'etude des proprietes electro-optiques liees a une telle separation spatiale des electrons et des trous. Un champ electrique perpendiculaire a pour consequence de scinder la transition optique fondamentale d'un superreseau de type ii en deux composantes, l'une se decalant vers les hautes energies (blue-shift) et l'autre vers les basses energies (red-shift). Il est alors remarquable que la transition a plus haute energie devienne la plus forte, grace a un meilleur recouvrement des fonctions d'onde. La plus grande partie des travaux presentes ici a toutefois ete consacree a une structure originale: un puits quantique de type ii constitue d'une seule alternance gaas/alas. De tels puits peuvent accumuler de fortes densites de charges sous des excitations optiques continues relativement modestes. Dans un premier temps ce peuplement a ete etudie en details, notamment grace a ses consequences sur les proprietes optiques: fort blue-shift, elargissement des raies, passage d'une recombinaison indirecte a pseudo-directe ou indirecte a directe. Ces fortes densites de charges sont utilisees par la suite pour creer des champs electriques internes, et en particulier obtenir un effet photovoltaique a bascule, dont le signe est controle par la longueur d'onde d'excitation. La consequence la plus spectaculaire des champs photocrees est un effet de bistabilite electro-optique dans les structures a puits de type ii, dont une caracteristiques remarquable est qu'elle s'obtient sans aucune polarisation electrique exterieure
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Nemitz, Ian R. "Synthesis of Nanoscale Semiconductor Heterostructures for Photovoltaic Applications." Bowling Green State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1277087935.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Diederich, Geoffrey M. "Synthesis of Zinc Telluride/Cadmium Selenide/Cadmium Sulfide Quantum Dot Heterostructures for use in Biological Applications." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1342542873.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
5

Fuchs, Christian [Verfasser], and Wolfgang [Akademischer Betreuer] Stolz. "Epitaxial growth and characterization of GaAs-based type-II (GaIn)As/Ga(AsSb)/(GaIn)As “W”-quantum well heterostructures and lasers / Christian Fuchs ; Betreuer: Wolfgang Stolz." Marburg : Philipps-Universität Marburg, 2018. http://d-nb.info/1171424728/34.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Arnoult, Alexandre. "Dopage par modulation d'hétérostructures de semiconducteurs II-VI semimagnétiques en épitaxie par jets moléculaires." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10237.

Повний текст джерела
Анотація:
Une etude theorique preliminaire a cette these a prevu que lorsque l'on introduit un gaz de trous bidimensionnel (2d) dans un puits quantique de semiconducteur semimagnetique, l'interaction entre les spins localises et les porteurs de charges induit une transition de phase ferromagnetique. Nous avons mis au point l'elaboration d'un tel systeme a base de tellurures en epitaxie par jets moleculaires, ainsi que la caracterisation au niveau microscopique des interfaces, du dopage et du transfert de porteurs dans le puits quantique. Ceci nous a permis d'elaborer des echantillons ayant donne lieu a toute une serie d'etudes physiques. Le dopage par modulation d'heterostructures de semiconducteurs ii-vi a base de tellure en epitaxie par jets moleculaires n'avait ete realise jusqu'a notre etude que pour un dopage de type n, sur des structures comportant du cdmgte comme materiau barriere, avec peu de magnesium. Or cet alliage est la clef de la realisation d'un bon confinement quantique dans les tellurures, surtout pour le dopage de type p ou la concentration en mg doit etre augmentee. L'utilisation d'une source d'azote ecr, dopant de type p, et l'optimisation des parametres de la croissance ont permis l'obtention d'un gaz de trous 2d de bonne densite, comme le montrent la spectroscopie optique, l'effet hall et la capacite-tension. L'etude de structures interdiffusees par sims, diffraction de rayon x et spectroscopie optique, nous a de plus permis de mieux comprendre les mecanismes de degradation en cours de croissance de nos couches comportant du magnesium, et dopees a l'azote. Un modele base sur la diffusion de l'azote a ete propose. Il a ensuite ete possible de realiser des structures semimagnetiques dans lesquelles l'interaction entre un gaz de trous 2d et des spins localises de manganese a permis la mise en evidence de la transition de phase ferromagnetique attendue theoriquement. Par ailleurs, un nouveau dopant de type n pour l'epitaxie par jets moleculaire des tellurures a ete teste avec succes sur des couches epaisses, ainsi que pour des heterostructures. Il s'agit de l'aluminium, dont le domaine d'utilisation est plus etendu que les autres dopants utilises jusqu'a present, puisqu'il permet d'obtenir une bonne efficacite meme sur des couches comportant du magnesium.
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Godoy, Marcio Peron Franco de. "Propriedades de pontos quânticos de InP/GaAs." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277715.

Повний текст джерела
Анотація:
Orientador: Fernando Iikawa
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-06T18:02:06Z (GMT). No. of bitstreams: 1 Godoy_MarcioPeronFrancode_D.pdf: 4057709 bytes, checksum: 0df1e56082150d4109dcf891f05d4da6 (MD5) Previous issue date: 2006
Resumo: Neste trabalho estudamos as propriedade estruturais e ópticas de pontos quânticos auto-organizados de InP crescidos sobre o substrato de GaAs. Esta estrutura apresenta o alinhamento de bandas tipo-II na interface, confinando o elétron no ponto quântico, enquanto o buraco mantém-se na barreira, próximo à interface devido à interação coulombiana atrativa. As amostras foram crescidas por epitaxia de feixe químico (CBE) no modo Stranskii-Krastanov. Os pontos quânticos apresentam raio médio de 25 nm e grande dispersão de altura (1-5 nm) e ocorre a relaxação parcial do parâmetro de rede, chegando a 2 %, em pontos quânticos superficiais. Do ponto de vista de propriedades ópticas, a fotoluminescência de pontos quânticos superficiais exibe uma eficiente emissão óptica, devido a baixa velocidade de recombinação dos estados superficiais do InP, e reflete a densidade e distribuição bimodal de tamanhos. Além disso, sua emissão óptica em função da intensidade de excitação exibe comportamento diverso em comparação com pontos quânticos cobertos com uma camada de GaAs. Em pontos quânticos cobertos, determinamos a energia de ativação térmica, que varia de 6 a 8 meV, e é associada à energia de ligação do éxciton ou energia de ionização do buraco. O decaimento temporal da luminescência de pontos quânticos é de 1,2 ns, um tempo relativamente curto para um ponto quântico tipo-II. A análise das propriedades magneto-ópticas em pontos quânticos individuais, inédita em QDs tipo-II, permitiu verificar que o fator-g do éxciton é praticamente constante, independentemente do tamanho dos QDs, devido ao fato dos buracos estarem levemente ligados. Por fim, mostramos a versatilidade do sistema acoplando-o a um poço quântico de InGaAs. Este acoplamento introduz mudanças na superposição das funções de onda do par elétron-buraco que permitem a manipulação do tempo de decaimento da luminescência e da energia de ligação excitônica
Abstract: We have investigated structural and optical properties of InP self-assembled quantum dots grown on GaAs substrate. This system presents a type-II band lineup where only electrons are confined in the InP quantum dots. The InP/GaAs quantum dots were grown by chemical beam epitaxy in the Stranskii-Krastanov mode. Our quantum dots present a mean radius of 25 nm and large height dispersion, 1-5 nm, and a partial relieve of the strain up to 2 % is observed. The photoluminescence spectra of surface quantum dots show an efficient optical emission, which is attributed to the low surface recombination velocity in InP. We observed a bimodal dispersion of the dots size distribution, giving rise to two distinct emission bands. A remarkable result is the relatively large blue shift of the emission band from uncapped samples as compared to those for capped dots. In capped quantum dots, we obtained the thermal activation energy, from 6 to 8 meV, which is associated to the exciton binding energy or hole ionization energy. The observed luminescence decay time is about 1.2 ns, relatively short decay time for type II system. We investigated magneto-optical properties using single-dot spectroscopy. The values of the exciton g factor obtained for a large number of single InP/GaAs dots are mainly constant independent of the emission energy and, therefore, of the quantum dot size. The result is attributed to the weak confinement of the holes in InP/GaAs QDs. We have also investigated structures where InP quantum dots are coupled to a InGaAs quantum well. This system permits the manipulation of the wave function overlap between electron-hole in order to control the optical emission decay time and exciton binding energy
Doutorado
Física
Doutor em Ciências
Стилі APA, Harvard, Vancouver, ISO та ін.
8

Eley, Clive William. "The rational design of photocatalytic semiconductor nanocrystals." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:ee29c922-857c-432a-8316-a7e04c822b1d.

Повний текст джерела
Анотація:
This thesis reports the successful rational design of three highly active photocatalytic semiconductor nanocrystal (SNC) systems by exploiting morphology effects and the electronic properties of type II semiconductor heterojunctions. Novel architectures of colloidal SNCs are produced with the aim of suppressing exciton recombination and improving charge extraction for the successful initiation of desirable redox chemistry. Rod-shaped niobium pentoxide Nb2O5 nanocrystals (NCs) are shown to exhibit significantly enhanced activity (10-fold increase in rate constant) relative to spherical-shaped NCs of the same material. The increase is attributed to Nb5+ Lewis acid site rich (001) surfaces, present in higher proportions in the rod morphology, which bind organic substrates from solution resulting in direct interaction with photogenerated charges on the surface of the NC. Building on the insights into morphology-activity dependence, type II semiconductor heterojunctions are exploited for their ability to increase exciton lifetimes and spatially separate charges. Two novel II-VI heterostructured semiconductor nanocrystals (HSNCs) systems are investigated: a series of CdX/ZnO (X = S, Se, Te) HSNCs and ZnS/ZnO HSNCs capped with two different surface ligands. In the first case, substantial photocatalytic activity improvement is observed for HSNCs (relative to pure ZnO analogues) according to the following trend: CdTe/ZnO > CdS/ZnO > CdSe/ZnO. The observed trend is explained in terms of heterojunction structure and fundamental chalcogenide chemistry. In the second case, both ZnS/ZnO HSNCs exhibit activity enhancement over analogous pure ZnO, but the degree of enhancement is found to be a function of surface ligand chemistry. Photocatalytic activity testing of all the materials investigated in this work is performed via the photodecomposition of methylene blue dye in aerated aqueous conditions under UVA (350 nm) irradiation. The synthetic techniques employed for the synthesis of colloidal SNCs investigated in this thesis range from chemical precipitation and solvothermal techniques to several different organometallic approaches. A wide variety of analytical techniques are employed for the chemical, structural and optical characterisation of SNC photocatalysts including: XRD, XPS, TEM, UV-vis absorption, PL spectroscopy and FTIR. Atom Probe Tomography (APT) is employed for the first time in the structural characterisation of II-VI heterojunctions in colloidal HSNCs. Overall, this thesis provides a useful contribution to the growing body of knowledge pertaining to the enhancement of photocatalytic SNCs for useful applications including: solar energy conversion to chemical fuels, the photodecomposition of pollutants and light-driven synthetic chemistry.
Стилі APA, Harvard, Vancouver, ISO та ін.
9

O'Connor, Timothy F. III. "Synthesis and Dynamics of Photocatalytic Type-II ZnSe/CdS/Pt Metal-Semiconductor Heteronanostructures." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1340038781.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Nogaret, Alain. "Etude comparée du transport par effet tunnel résonnant dans les hétérostructures semiconductrices de type I et II en présence de pression hydrostatique et de fort champ magnétique." Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0037.

Повний текст джерела
Анотація:
Nous etudions la combinaison de l'effet tunnel resonnant avec l'effet tunnel interbande dans les heterostructures presentant un alignement de type ii. Dans les heterostructures de type i, la quantification magnetique montre qu'un electron avec une importante energie cinetique transverse conserve son energie plutot que son vecteur d'onde transverse, la pression hydrostatique met en evidence un pic de courant extraordinaire que nous attribuons a la formation de niveaux x lies dans les barrieres alas, le calcul clarifie la contribution des modes de phonons lo locaux au courant vallee. Nous exposons les procedes lithographiques que nous avons mis au point pour elaborer le systeme inas/alsb/gasb. Nous soulignons l'importance du choix de l'energie de fermi dans les electrodes et ses multiples consequences sur la forme des caracteristiques courant-tension des heterostructures de type ii. Nos resultats devoilent les mecanismes physiques responsables du courant resonnant interbande et suggerent l'existence d'une bande interdite d'hybridation due au couplage electron-trou. Nous interpretons l'effet tunnel interbande a travers des sous-bandes de trous par les regles de selection usuelles et observons pour la premiere fois la bistabilite intrinseque dans une structure de type ii. Ces resultats nous amenent a comparer les performances de dispositifs electroniques utilisant soit l'effet tunnel resonnant soit l'effet tunnel resonnant interbande
Стилі APA, Harvard, Vancouver, ISO та ін.

Частини книг з теми "Type II Heterostructures"

1

Mendez, E. E., H. Ohno, L. Esaki, and W. I. Wang. "Resonant Magnetotunneling in Type II Heterostructures." In Resonant Tunneling in Semiconductors, 51–60. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3846-2_5.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Zhang, Yong. "ZnO and GaN Nanowire-Based Type II Heterostructures." In Wide Band Gap Semiconductor Nanowires 2, 85–103. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118984291.ch4.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Heuring, W., E. Bangert, G. Landwehr, G. Weimann, and W. Schlapp. "p-Type GaAs-(GaAI)As Heterostructures in Tilted Magnetic Fields: Theory and Experiments." In High Magnetic Fields in Semiconductor Physics II, 190–93. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-83810-1_30.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Roberts, M., N. J. Mason, S. G. Lyapin, Y. C. Chung, and P. C. Klipstein. "Vertical transport and interband luminescence in type II InAs/GaSb/InAs heterostructures." In Springer Proceedings in Physics, 829–30. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59484-7_393.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
5

Ossau, W., T. L. Kuhn, E. Bangert, and G. Weimann. "The H-Band Luminescence of p-Type GaAs-(GaAl)As Heterostructures in High Magnetic Fields." In High Magnetic Fields in Semiconductor Physics II, 268–77. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-83810-1_41.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Akimoto, R., Y. Kinpara, and K. Akita. "Large quantum confinement effect of conduction electrons in ZnSe/BeTe type II heterostructures." In Springer Proceedings in Physics, 471–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59484-7_220.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Gourdon, C., D. Martins, V. Voliotis, P. Lavallard, and E. L. Ivchenko. "Oscillatory behavior of the Г-X coupling with AlAs thickness in type II GaAs/AlAs heterostructures." In Springer Proceedings in Physics, 515–16. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59484-7_242.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
8

Teissier, R., R. Planel, and F. Mollot. "All Optical Bistability in a Type II Heterostructure." In Optical Information Technology, 265–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-78140-7_29.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
9

Singh, Amit Kumar, Rohit Singh, Dibyendu Chowdhury, and Amit Rathi. "Optical Response in Strained Type-II AlInAs/AlSb Ultrathin QW Heterostructure." In Lecture Notes in Electrical Engineering, 569–75. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-0588-9_56.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Yadav, Nisha, Garima Bhardwaj, S. G. Anjum, K. Sandhya, M. J. Siddiqui, and P. A. Alvi. "Quantum Well Width Effect on Intraband Optical Absorption in Type-II InAs/AlSb Nano-Scale Heterostructure." In Lecture Notes in Electrical Engineering, 191–97. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7395-3_22.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.

Тези доповідей конференцій з теми "Type II Heterostructures"

1

Hirst, Louise C., Michael K. Yakes, Chaffra A. Affouda, Christopher G. Bailey, Joseph G. Tischler, Hamidreza Esmaielpour, Vincent R. Whiteside, et al. "Hot-carrier effects in type II heterostructures." In 2015 IEEE 42nd Photovoltaic Specialists Conference (PVSC). IEEE, 2015. http://dx.doi.org/10.1109/pvsc.2015.7356231.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Ahn, H. S., M. S. Park, and J. H. Jang. "Phototransistors based on InP/GaAsSb/InGaAs type-II heterostructures." In Related Materials (IPRM). IEEE, 2008. http://dx.doi.org/10.1109/iciprm.2008.4703037.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Nussbaum, Simon. "Towards organic-inorganic hybrid type-II layered perovskite nano-heterostructures." In MATSUS23 & Sustainable Technology Forum València (STECH23). València: FUNDACIO DE LA COMUNITAT VALENCIANA SCITO, 2022. http://dx.doi.org/10.29363/nanoge.matsus.2023.029.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Shterengas, L., A. Ongstad, R. Kaspi, S. Suchalkin, G. Belenky, M. Kisin, and D. Donetsky. "Carrier capture in InGaAsSb/InAs/InGaSb type-II QW laser heterostructures." In 2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference. IEEE, 2006. http://dx.doi.org/10.1109/cleo.2006.4628718.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
5

Duggan, G., and H. I. Ralph. "Exciton Binding Energy In Type-II GaAs-AlAs Quantum Well Heterostructures." In Semiconductor Conferences, edited by Gottfried H. Doehler and Joel N. Schulman. SPIE, 1987. http://dx.doi.org/10.1117/12.940833.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Zheng, Jun, C. H. T. Lin, and Shin Shem Pei. "Simulations of InAs/InGaSb type-II heterostructures for mid-IR lasers." In Optoelectronics '99 - Integrated Optoelectronic Devices, edited by Peter Blood, Akira Ishibashi, and Marek Osinski. SPIE, 1999. http://dx.doi.org/10.1117/12.356917.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Miles, R. H., and M. E. Flatté. "Type-II Superlattices for Infrared Optoelectronics and Lasers." In Quantum Optoelectronics. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/qo.1997.qfa.3.

Повний текст джерела
Анотація:
Interest in broken-gap, type-II heterostructures for optoelectronic applications is predicated largely on their promise as infrared lasers, detectors, and modulators appreciably outperforming conventional devices. Cryogenic imaging arrays based on these structures are projected to perform with higher detectivities and/or at higher operating temperatures than competing systems based on HgCdTe or extrinsic materials. Lasers in the 3-5μm spectral band are expected to operate at or near room temperature with significant output powers, and modulators with unusually low insertion losses and high dynamic range have been proposed. Brought to maturity, applications of such devices would be numerous, ranging from environmental monitoring systems to short-link, high bandwidth optical communications.
Стилі APA, Harvard, Vancouver, ISO та ін.
8

Nanda, Jagjit, Sergei Ivanov, Ilya Bezel, and Victor I. Klimov. "Tunable optical gain and amplified spontaneous emission using type I and type II nanocrystal heterostructures." In International Quantum Electronics Conference. Washington, D.C.: OSA, 2004. http://dx.doi.org/10.1364/iqec.2004.ithc2.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
9

Titkov, A. N., Yury P. Yakovlev, Alexej N. Baranov, and V. N. Cheban. "Tunneling recombination of carriers at type-II interface in GaInAsSb-GaSb heterostructures." In Physical Concepts of Materials for Novel Optoelectronic Device Applications, edited by Manijeh Razeghi. SPIE, 1991. http://dx.doi.org/10.1117/12.24429.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Liu, Hui C., Emmanuel Dupont, John P. McCaffrey, Margaret Buchanan, Dongxu Zhang, Rui Q. Yang, C. H. T. Lin, Stefan J. Murry, and Shin Shem Pei. "Mid-infrared interband cascade emission in InAs/GaInSb/AlSb type-II heterostructures." In Optoelectronics and High-Power Lasers & Applications, edited by Hong K. Choi and Peter S. Zory. SPIE, 1998. http://dx.doi.org/10.1117/12.304456.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Також вас можуть зацікавити розширені добірки на тему "Type II Heterostructures" для конкретних типів джерел:
Статті в журналах
Ми пропонуємо знижки на всі преміум-плани для авторів, чиї праці увійшли до тематичних добірок літератури. Зв'яжіться з нами, щоб отримати унікальний промокод!

До бібліографії