Os experimentos foram realizados no Dynamics Química Beamline na Fonte de Luz Avançado, Lawrence Berkeley National Laboratory e apoiado pelo Escritório de Ciência, Instituto de ciências básicas da energia, do Departamento de Energia dos EUA sob Contrato n º DE-AC02-05CH11231, através da Divisão de Ciências Químicas.

1. Carregando Amostra <ol><li> Remover a flange traseira e desmontar a 3/8 &quot;tubo de bocal inoxidável a partir do aparelho (ver Figura 1 e Figura 2) e se certificar que está limpo e o orifício de 100 mm, é claro (Isto pode ser feito examinando uma fonte de luz através lo). Para limpeza, encher o tubo com um ~ ml de etanol e esfregar o interior com pontas de algodão. Alternativamente, coloque o bocal em banho de ultra-sons cheio com água e sabão ou etanol durante cerca de 20 min. Então seca com ar comprimido. </li><li> Utilizando uma pequena espátula limpo lugar, a cerca de 250 mg de amostra, na parte frontal do bocal, perto do orifício, mas não bloqueando. Um bom método para evitar o orifício de ficar bloqueado é colocar uma bola pequena folha de alumínio ou de lã de vidro, em frente do orifício e em seguida, adicionar o pó de amostra. Utilizar uma ponta de algodão para empurrar a amostra para dentro do tubo para assegurar que está na frente de 25 mm do tubo. Esta parte da frente vão compor o aquecidazona. </li><li> Volte a ligar o bocal do aparelho com cuidado para evitar o movimento da amostra em pó no interior. Em seguida, conecte o adaptador de gaiola (ver Figura 2), bloco de aquecimento e termopar (ver Figura 3). </li><li> Antes de fechar a câmara de vácuo, medir a distância entre a superfície da flange da ponta do bocal para ser 22,5 polegadas, o que irá permitir a 0,5 polegadas entre o bocal e o skimmer. </li><li> Quando a câmara de vácuo é fechada, testar o cartucho aquecedor e conexões de termopares para se certificar que estão bem ligados aos conectores de alimentação através de. </li><li> Verifique se o portador da válvula de entrada de gás está fechado. </li><li> Fechar a válvula de ventilação (se tiver sido utilizado). </li><li> Lentamente começar a bombear a câmara utilizando as bombas de desbaste (4 válvulas), e quando a pressão na câmara é &lt;1 torr, iniciar as bombas turbomoleculares (5 bombas). </li><li> Quando a pressão na câmara é de &lt;10 -6 torr, aplicar as voltagens para a óptica de iõesdo tempo de voo de espectrometria de massa, e um detector de placa de micro-canais (a tensão sobre esta última deve ser ligado gradualmente) (Ver Figura 1 para várias tensões). </li><li> Abrir o obturador VUV para permitir que o feixe de fotões na câmara. </li><li> Abrir a válvula de entrada de gás portador e definir o regulador de pressão de suporte de 460 (este é um regulador de vácuo, medindo em uma escala de 0 a negativa -760 torr, portanto, quando fixado a 460 irá regular a pressão na linha e 300 torr) . </li><li> Sob estas condições, a pressão nas câmaras do espectrómetro de massa de origem e deve ser ~ 1 x 10 -6 torr e ~ 1 x 10 -6 torr, respectivamente. </li></ol> 2. Aquisição de um Espectro de Massa <ol><li> Comece o cartão FAST (número do modelo P7889, 100 ps / bin) software no computador e deixá-lo correr em segundo plano. </li><li> Abra o Labview programa de aquisição de dados: &quot;General Interface.vi&quot; * (figura 4) </li></ol><html> (* Este software e outros códigos Labview foram desenvolvidos na linha de luz e estão disponíveis para compartilhar, sem nenhum custo a partir do autor correspondente) <ol start="3"><li> Usando a guia de controle ALS no software Labview, definir a energia do fóton para o comprimento de onda desejado. </li><li> Na guia scaler, definir o número de unidades de tempo a ser binned juntos (tipicamente 32), o intervalo (número de caixas) e varrimentos (o número de espectros de massa adicionado em cima uns dos outros para formar o espectro de massa final), depois clique aceitar, de modo que estes valores serão armazenados e utilizados. </li><li> Em seguida, clique em obter dados para iniciar a aquisição de dados. Quando a aquisição é longo, o espectro de massa aparecerá no ecrã. </li><li> Salve o espectro de massa, clicando no botão salvar. (O eixo X do espectro obtido corresponde ao tempo de voo de iões em unidades de 100 ps) </li></ol>tle &quot;&gt; 3 Aquisição. de uma curva de eficiência de fotoionização (PIE) <ol><li> Usando o ALS separador Scan (Figura 5) no software Labview, é possível adquirir dados durante a afinação um dos motores beamline. Neste caso, selecione o motor &quot;energia Mono T3&quot; para sintonizar mais diferentes energias de fótons (O ondulador dentro do síncrotron se move automaticamente para coincidir com o comprimento de onda desejado). Estabelecer a energia de fotões para o valor desejado (em eV). </li><li> Digite o Start e energias de parada (em eV), bem como o tamanho do passo. </li><li> Não digite o número de varreduras - este será atualizado automaticamente pelo valor inserido na etapa 2.4. </li><li> Clique Ler corrente de K486 para ler a fotocorrente medido pelo fotodiodo. </li><li> Em seguida, clique em Iniciar para iniciar a digitalização. Você será solicitado a escolher um nome de arquivo onde os dados serão armazenados no final da corrida. </li><li> A primeira coluna no arquivo de dados conTain o número bin (Bin #) e precisam ser convertidos em unidades de massa 13. Os valores típicos são os seguintes: Massa = 0,6 + 1xE-3 (Bin #) + 5xE-7 (Bin #) ^ 2 (A calibração de massa mais preciso pode ser feito usando uma mistura conhecida de gases ou de ar ambiente, mesmo na maior parte ie O 2, N 2 e H 2 O e montagem mistura a sua hora de chegada para um polinômio de segunda ordem) </li><li> Salve o arquivo de dados com a primeira coluna convertida em massa. </li><li> Para traçar uma curva de TORTA, uma maneira fácil é usar um programa Labview segunda chamada &quot;energia ALS scan.vi&quot;, que é projetado para analisar os dados de digitalização e produzir EIP. </li></ol> 4. Traçando uma curva de eficiência de fotoionização (PIE) <ol><li> Como mencionado acima, a análise pode ser feita utilizando o &quot;ALS energia scan.vi&quot; do programa (ver a Figura 6), no entanto, vamos descrever aqui também os passos necessários para a análise dos dados sem ele. </li><li> Ao iniciar o programa, você será solicitado a selecionar o arquivo containing dos dados. Este é o arquivo que você salvou no passo 3,7 e conter massas nas primeiras contagens de coluna e de íons em diferentes energias de fótons nas próximas colunas. Note-se que as primeira e segunda linhas no arquivo de indicar a energia de fotões e fotocorrente dos dados dessa coluna, respectivamente. </li><li> No painel superior, há um gráfico de 2D dos dados; mover o marcador vermelho horizontal selecciona um espectro de massa de um fotão específico de energia a ser exibido no painel inferior. </li><li> O passo seguinte consiste em integrar as contagens de iões com uma massa específica de cada fotão de energia enquanto subtraindo o sinal de fundo. No painel inferior das duas verticais marcadores vermelhos deve ser ajustado em torno do pico de massa a ser integrado, enquanto os dois marcadores azul em torno de uma região próxima sem dados que podem servir como valor de fundo. O software irá apresentar os dados integrados menos a fundo no painel à direita. </li><li> Para apresentar uma curva TORTA verdade é preciso corrigir as contagens de íons para o fluxo de fótons variando umt cada passo. Isso é feito automaticamente pelo software. Se você optar por ignorar esta correção, clique para desligar o botão de correção atual, à direita do painel superior. Se você optar por fazer este passo manualmente, a eficiência quântica do fotodiodo por energia do fóton tem que ser considerado, bem como (obtidos com o fabricante fotodiodo e disponível através do autor correspondente), ver equação 1. Caso contrário, tudo isto é feito automaticamente pelo software. </li></ol><img alt="Equação 1" fo:src="/files/ftp_upload/50164/50164eq1highres.jpg" src="/files/ftp_upload/50164/50164eq1.jpg" /><ol start="6"><li> Clique em salvar espectro no canto inferior direito para salvar a curva PIE corrigida. </li></ol>

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	<li>Golan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ionization+of+dimethyluracil+dimers+leads+to+facile+proton+transfer+in+the+absence+of+hydrogen+bonds.">Ionization of dimethyluracil dimers leads to facile proton transfer in the absence of hydrogen bonds.</a> Nat. 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Os monómeros e dímeros são gerados de uma expansão de jacto supersónico que dá origem a um feixe molecular. Uma pequena amostra da base de ADN é colocado numa fonte de vaporização térmica e aqueceu-se a gerar uma pressão de vapor suficiente. Argon transporta os vapores de gás através de um orifício de 100 ^ M e passa um skimmer mm 2 para produzir um feixe frio molecular 14. Em alternativa, uma fonte de feixe efusivo pode ser utilizado, em que a amostra é colocada num forno aquecido ligado à pl...

<table border="1"&gt;<tr&gt;<td<strong&gt; Nome do Reagente / Material</strong</td&gt;<td<strong&gt; Empresa</strong</td&gt;<td<strong&gt; Número de catálogo</strong</td&gt;<td<strong&gt; Comentários</strong</td&gt;</tr&gt;<tr&gt;<td&gt; Uracila</td&gt;<td&gt; Sigma</td&gt;<td&gt; U0750</td&gt;<td</td&gt;</tr&gt;<tr&gt;<td&gt; 1,3 dimetil-</td&gt;<td&gt; Aldrich</td&gt;<td&gt; 349801</td&gt;<td</td&gt;</tr&gt;</table

molecular beam mass spectrometry with tunable vacuum ultraviolet (vuv) synchrotron radiation

Ionização suave Tunable acoplada a espectrometria de massa é um poderoso método para investigar moléculas isoladas, complexos e clusters e sua espectroscopia dinâmica e 1-4. Estudos fundamentais dos processos de fotoionização de biomoléculas fornecer informações sobre a estrutura eletrônica desses sistemas. Além disso determinações de energias de ionização e outras propriedades de biomoléculas em fase gasosa não é trivial, e estas experiências proporcionam uma plataforma para gerar esses dados. Nós desenvolvemos uma técnica de vaporização térmica combinada com supersónicas feixes moleculares que proporciona uma forma suave para o transporte destas espécies para a fase gasosa. Combinação judiciosa de fonte de gás e da temperatura permite a formação de dímeros e agregados mais elevados de bases de DNA. O foco principal deste trabalho é determinado sobre os efeitos das interacções não covalentes, isto é, ligação de hidrogénio, empilhamento, e as interacções electrostáticas, sobre as energias de ionização etransferência de prótons de biomoléculas individuais, seus complexos e ao micro-hidratação por água 1, 5-9. Efetuamos caracterização experimental e teórico da dinâmica de fotoionização de fase gasosa uracil e 1,3 dimetil-dímeros usando feixes moleculares, juntamente com radiação síncrotron no Dynamics Química Beamline 10 localizado na fonte avançada Luz e os detalhes experimentais são visualizados aqui. Isso nos permitiu observar a transferência de prótons em 1,3 dimetil-dímeros, um sistema com empilhamento pi geometria e sem ligações de hidrogênio 1. Feixes moleculares fornecem uma maneira muito conveniente e eficiente para isolar a amostra de interesse a partir de perturbações ambientais, que em troca permite uma comparação exacta com cálculos de estrutura electrónica 11, 12. Ao ajustar a energia dos fótons da luz síncrotron, uma eficiência de fotoionização (PIE) da curva pode ser traçada, que nos informa sobre a catiônicaestados eletrônicos. Estes valores podem então ser comparadas com os modelos teóricos e cálculos e, por sua vez, explicar em pormenor a estrutura electrónica e da dinâmica das espécies investigadas 1, 3.

A Figura 7 mostra um espectro de massa típico de expansão supersónica de 1,3-dimetil vapores (A) e as curvas de pizza das três características principais do monómero (a m / z 140, monómero protonado a m / z 141, e a uma dimetiluracilo ,3-dímero a m / z 280), como uma verificação extraída VUV entre 8 e 10 eV eV (B). A sombra cinza é o desvio padrão de três exames consecutivos. <img alt="Figura 1" fo:content-width="5in" fo:src...

Watch this Scientific Journal Video about Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet VUV Synchrotron Radiation at JoVE.com

Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet VUV Synchrotron Radiation

Um feixe molecular acoplado a espectrômetro de massa de vácuo ajustável ultravioleta fotoionização em um síncrotron disponibiliza uma ferramenta útil para explorar a estrutura eletrônica de moléculas de gás isoladas de fase e clusters. Mecanismos de transferência de protões em dímeros de bases do DNA foram elucidadas com esta técnica.

Espectrometria de Massa Molecular Beam Com Tunable radiação ultravioleta de vácuo Síncrotron (VUV)

Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy ...

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Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation

12.9K visualizações.  Lawrence Berkeley National Laboratory. Um feixe molecular acoplado a espectrômetro de massa de vácuo ajustável ultravioleta fotoionização em um síncrotron disponibiliza uma ferramenta útil para explorar a estrutura eletrônica de moléculas de gás isoladas de fase e clusters. Mecanismos de transferência de protões em dímeros de bases do DNA foram elucidadas com esta técnica.

Vídeo: Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet VUV Synchrotron Radiation

Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. During insertion or removal of alkali metal ions, the redox states of transition metals in the compounds change and structural transformations such as phase transitions and/or lattice parameter increases or decreases occur. These behaviors in turn determine important characteristics of the batteries such as the potential profiles, rate capabilities, and cycle lives. The extremely bright and tunable x-rays produced by synchrotron radiation allow rapid acquisition of high-resolution data that provide information about these processes. Transformations in the bulk materials, such as phase transitions, can be directly observed using X-ray diffraction (XRD), while X-ray absorption spectroscopy (XAS) gives information about the local electronic and geometric structures (e.g.&#160;changes in redox states and bond lengths). In situ experiments carried out on operating cells are particularly useful because they allow direct correlation between the electrochemical and structural properties of the materials. These experiments are time-consuming and can be challenging to design due to the reactivity and air-sensitivity of the alkali metal anodes used in the half-cell configurations, and/or the possibility of signal interference from other cell components and hardware. For these reasons, it is appropriate to carry out ex situ experiments (e.g.&#160;on electrodes harvested from partially charged or cycled cells) in some cases. Here, we present detailed protocols for the preparation of both ex situ and in situ samples for experiments involving synchrotron radiation and demonstrate how these experiments are done.

We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li-ion and Na-ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices

Caracterização de Materiais de Eletrodo de íons de lítio e íon sódio Baterias Utilizando Técnicas Synchrotron Radiation

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. ...

Engenharia

Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities

Owing to its relativistic low-energy charge carriers, the interaction between graphene and various impurities leads to a wealth of new physics and degrees of freedom to control electronic devices. In particular, the behavior of graphene&#8217;s charge carriers in response to potentials from charged Coulomb impurities is predicted to differ significantly from that of most materials. Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) can provide detailed information on both the spatial and energy dependence of graphene&#39;s electronic structure in the presence of a charged impurity.&#160;The design of a hybrid impurity-graphene device, fabricated using controlled deposition of impurities onto a back-gated graphene surface, has enabled several novel methods for controllably tuning graphene&#8217;s electronic properties.1-8 Electrostatic gating enables control of the charge carrier density in graphene and the ability to reversibly tune the charge2 and/or molecular5 states of an impurity. This paper outlines the process of fabricating a gate-tunable graphene device decorated with individual Coulomb impurities for combined STM/STS studies.2-5 These studies provide valuable insights into the underlying physics, as well as signposts for designing hybrid graphene devices.

This paper details the fabrication process of a gate-tunable graphene device, decorated with Coulomb impurities for scanning tunneling microscopy studies. Mapping the spatially dependent electronic structure of graphene in the presence of charged impurities unveils the unique behavior of its relativistic charge carriers in response to a local Coulomb potential.

Fabricação de porta-ajustáveis ​​dispositivos de grafeno para tunelamento estudos de microscopia com Coulomb Impurezas

Owing to its relativistic low-energy charge carriers, the interaction between graphene and various impurities leads to a wealth of new physics and degrees ...

Failure Analysis of Batteries Using Synchrotron-based Hard X-ray Microtomography

Imaging morphological changes that occur during the lifetime of rechargeable batteries is necessary to understand how these devices fail. Since the advent of lithium-ion batteries, researchers have known that the lithium metal anode has the highest theoretical energy density of any anode material. However, rechargeable batteries containing a lithium metal anode are not widely used in consumer products because the growth of lithium dendrites from the anode upon charging of the battery causes premature cell failure by short circuit. Lithium dendrites can also form in commercial lithium-ion batteries with graphite anodes if they are improperly charged. We demonstrate that lithium dendrite growth can be studied using synchrotron-based hard X-ray microtomography. This non-destructive imaging technique allows researchers to study the growth of lithium dendrites, in addition to other morphological changes inside batteries, and subsequently develop methods to extend battery life.

Synchrotron-based hard X-ray microtomography is used to image the electrochemical growth of dendrites from a lithium metal electrode through a solid polymer electrolyte membrane.

Falha Análise de Baterias Usando baseado no Synchrotron microtomografia de raios-X dura

Imaging morphological changes that occur during the lifetime of rechargeable batteries is necessary to understand how these devices fail. Since the advent ...

Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can potentially contribute to the exposure of biota and humans. The diffusive gradients in thin films technique is introduced here for in-situ measurements of Pu bioavailability and speciation. A diffusion cell constructed for laboratory experiments with Pu and the newly developed protocol make it possible to simulate the environmental behavior of Pu in model solutions of various chemical compositions. Adjustment of the oxidation states to Pu(IV) and Pu(V) described in this protocol is essential in order to investigate the complex redox chemistry of plutonium in the environment. The calibration of this technique and the results obtained in the laboratory experiments enable to develop a specific DGT device for in-situ Pu measurements in freshwaters. Accelerator-based mass-spectrometry measurements of Pu accumulated by DGTs in a karst spring allowed determining the bioavailability of Pu in a mineral freshwater environment. Application of this protocol for Pu measurements using DGT devices has a large potential to improve our understanding of the speciation and the biological transfer of Pu in aquatic ecosystems.

The technique of diffusive gradients in thin films (DGT) is proposed for speciation studies of plutonium. This protocol describes diffusion experiments probing the behavior of Pu(IV) and Pu(V) in presence of organic matter. DGTs deployed in a karstic spring allow assessment of the bioavailability of Pu.

Especiação e biodisponibilidade Medidas de plutônio ambiental utilizando Difusão em Filmes Finos

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can ...

Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. Conventionally reserved for the fabrication of metal thin films, thermal evaporation deposits bismuth into an array of vertical single crystalline nanowires over a flat thin film of vanadium held at RT, which is freshly deposited by magnetron sputtering or thermal evaporation. By controlling the temperature of the growth substrate the length and width of the nanowires can be tuned over a wide range. Responsible for this novel technique is a previously unknown nanowire growth mechanism that roots in the mild porosity of the vanadium thin film. Infiltrated into the vanadium pores, the bismuth domains (~ 1 nm) carry excessive surface energy that suppresses their melting point and continuously expels them out of the vanadium matrix to form nanowires. This discovery demonstrates the feasibility of scalable vapor phase synthesis of high purity nanomaterials without using any catalysts.

A protocol for seedless and high yield growth of bismuth nanowire arrays through vacuum thermal evaporation technique is presented.

Crescimento sem sementes de bismuto Nanowire matriz via vácuo evaporação térmica

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. ...

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm2, but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample&#39;s properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 &#181;m all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

For this study synchrotron radiation micro-tomography, a non-destructive three-dimensional imaging technique, is employed to investigate an entire microelectronic package with a cross-sectional area of 16 x 16 mm. Due to the synchrotron&#39;s high flux and brightness the sample was imaged in just 3 min&#160;with an 8.7 &#181;m spatial resolution.

Usando Synchrotron Radiation microtomografia para investigar Multi-escala Pacotes de microeletrônicos tridimensionais

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data ...

Plasma-assisted Molecular Beam Epitaxy of N-polar InAlN-barrier High-electron-mobility Transistors

Plasma-assisted molecular beam epitaxy is well suited for the epitaxial growth of III-nitride thin films and heterostructures with smooth, abrupt interfaces required for high-quality high-electron-mobility transistors (HEMTs). A procedure is presented for the growth of N-polar InAlN HEMTs, including wafer preparation and growth of buffer layers, the InAlN barrier layer, AlN and GaN interlayers and the GaN channel. Critical issues at each step of the process are identified, such as avoiding Ga accumulation in the GaN buffer, the role of temperature on InAlN compositional homogeneity, and the use of Ga flux during the AlN interlayer and the interrupt prior to GaN channel growth. Compositionally homogeneous N-polar InAlN thin films are demonstrated with surface root-mean-squared roughness as low as 0.19 nm and InAlN-based HEMT structures are reported having mobility as high as 1,750 cm2/V&#8729;sec for devices with a sheet charge density of 1.7 x 1013 cm-2.

Molecular beam epitaxy is used to grow N-polar InAlN-barrier high-electron-mobility transistors (HEMTs). Control of the wafer preparation, layer growth conditions and epitaxial structure results in smooth, compositionally homogeneous InAlN layers and HEMTs with mobility as high as 1,750 cm2/V&#8729;sec.

assistido por plasma Molecular Beam Epitaxy de N-polar InAlN barreiras Transistores de alta electron-mobility

Plasma-assisted molecular beam epitaxy is well suited for the epitaxial growth of III-nitride thin films and heterostructures with smooth, abrupt ...

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

Solid-state electrolytes are a promising replacement for current organic liquid electrolytes, enabling higher energy densities and improved safety of lithium-ion (Li-ion) batteries. However, a number of setbacks prevent their integration into commercial devices. The main limiting factor is due to nanoscale phenomena occurring at the electrode/electrolyte interfaces, ultimately leading to degradation of battery operation. These key problems are highly challenging to observe and characterize as these batteries contain multiple buried interfaces. One approach for direct observation of interfacial phenomena in thin film batteries is through the fabrication of electrochemically active nanobatteries by a focused ion beam (FIB). As such, a reliable technique to fabricate nanobatteries was developed and demonstrated in recent work. Herein, a detailed protocol with a step-by-step process is presented to enable the reproduction of this nanobattery fabrication process. In particular, this technique was applied to a thin film battery consisting of LiCoO2/LiPON/a-Si, and has further been previously demonstrated by in situ cycling within a transmission electron microscope.

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

A protocol for the fabrication of electrochemically active LiPON-based solid-state lithium-ion nanobatteries using a focused ion beam is presented.

Fabricação de feixe de íon focalizado de estado sólido baseados em LiPON de lítio-íon Nanobatteries para In Situ testes

Solid-state electrolytes are a promising replacement for current organic liquid electrolytes, enabling higher energy densities and improved safety of ...

Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex donor-acceptor emitters is presented. With a step-by-step procedure, readers will be able to repeat and produce OLED devices based on simple organic emitters. A patterning procedure allowing the creation of personalized indium tin oxide (ITO) shape is shown. This is followed by the evaporation of all layers, encapsulation and characterization of each individual device. The end goal is to present a procedure that will give the opportunity to repeat the information presented in cited publication but also using different compounds and structures in order to prepare efficient OLEDs.

A protocol for the production of simple structured organic light-emitting diodes (OLEDs) is presented.

Produção e caracterização de vácuo depositaram diodos emissores de luz orgânico

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex ...

Fabrication of Schottky Diodes on Zn-polar BeMgZnO/ZnO Heterostructure Grown by Plasma-assisted Molecular Beam Epitaxy

Heterostructure field effect transistors (HFETs) utilizing a two dimensional electron gas (2DEG) channel have a great potential for high speed device applications. Zinc oxide (ZnO), a semiconductor with a wide bandgap (3.4 eV) and high electron saturation velocity has gained a great deal of attention as an attractive material for high speed devices. Efficient gate modulation, however, requires high-quality Schottky contacts on the barrier layer. In this article, we present our Schottky diode fabrication procedure on Zn-polar BeMgZnO/ZnO heterostructure with high density 2DEG which is achieved through strain modulation and incorporation of a few percent Be into the MgZnO-based barrier during growth by molecular beam epitaxy (MBE). To achieve high crystalline quality, nearly lattice-matched high-resistivity GaN templates grown by metal-organic chemical vapor deposition (MOCVD) are used as the substrate for the subsequent MBE growth of the oxide layers. To obtain the requisite Zn-polarity, careful surface treatment of GaN templates and control over the VI/II ratio during the growth of low temperature ZnO nucleation layer are utilized. Ti/Au electrodes serve as Ohmic contacts, and Ag electrodes deposited on the O2 plasma pretreated BeMgZnO surface are used for Schottky contacts.

Attainment of high-quality Schottky contacts is imperative for achieving efficient gate modulation in heterostructure field effect transistors (HFETs). We present the fabrication methodology and characteristics of Schottky diodes on Zn-polar BeMgZnO/ZnO heterostructures with high-density two dimensional electron gas (2DEG), grown by plasma-assisted molecular beam epitaxy on GaN templates.

Fabricação de diodos de Schottky na Zn-polar BeMgZnO/ZnO Heterostructure cultivadas por Epitaxia de feixe Molecular assistido por Plasma

Heterostructure field effect transistors (HFETs) utilizing a two dimensional electron gas (2DEG) channel have a great potential for high speed device ...