Academic literature on the topic 'Semiconductor tipo n'

En este trabajo se desarrolló una herramienta de software que permite determinar las propiedades ópticas de materiales semiconductores, esta herramienta es de utilidad para investigadores que trabajan en la caracterización de películas delgadas semiconductoras. El software calcula las constantes ópticas: índice de refracción (n), coeficiente de absorción (α) y brecha de energía prohibida (Gap), además del espesor aproximado de la película; con el programa desarrollado se calcularon las constantes ópticas de películas delgadas de ZnS, SnS:Bi y SnS2:Bi, que son usadas como capas buffer y absorbentes en celdas solares, en este trabajo se presentan los resultados obtenidos con una película de SnS2:Bi. El software fue creado en el lenguaje de programación Python dentro de una interfaz sencilla inglés-español y para desarrollarlo se tuvo en cuenta el método propuesto por Swanepoel, el cual toma como base el espectro de transmitancia experimental del material semiconductor.

Se estudiaron las características eléctricas de películas delgadas de óxido de aluminio preparadas por la técnica de rocío pirolítico ultrasónico. Las películas delgadas se depositaron a partir de una solución de acetilacetonato de aluminio en N,N-dimetilformamida sobre substratos monocristalinos de GaAs (100) tipo-p. La temperatura de depósito fue de 300 a 600 ºC. Las propiedades eléctricas de las películas en función de la temperatura de substrato se determinaron por medidas de capacitancia y corriente contra voltaje mediante la incorporación de las películas en estructuras tipo MOS (metal-óxido-semiconductor). La densidad de estados de interfaz resultó del orden de 10(12) 1/eV-cm² y el dispositivo MOS soportó campos eléctricos mayores a 5MV/cm, sin mostrar rompimiento dieléctrico. El índice de refracción se determinó por elipsometría a 633nm, con un valor máximo del orden de 1.64.

In this paper the open, circular cross-section cylindrical gyro- electric p-GaAs (semiconductor-dielectric) waveguides with temperature-sensitive anisotropic dielectric layer are investigated. The gyroelectric phase shifters without anisotropic dielectric layer are not effective. The anisotropic layer increases the mode HE11 differential phase shift to 1060° and 1250°, when temperature T = (125–200) K, N = 5∙1019 and N = 1020 m–3 respectively. Propagated mode HE11 in gyroelectric p-GaAs waveguides, the attenuation coefficient increases, increasing the concentration of holes. The anisotropic dielectric layer reduces the mode attenuation, it is appropriate to create gyroelectric mode phase shifters with a lower hole concentration and anisotropic dielectric layer. Tiriami atvirieji, apskritojo skerspjūvio cilindriniai, giroelektriniai p-GaAs (puslaidininkiniai-dielektriniai) bangolaidžiai su jautriais temperatūrai puslaidininkine šerdimi ir anizotropiniu dielektriko sluoksniu. Šis sluoksnis padidina hibridinių pagrindinio tipo HE11 bangų diferencinį fazės pokytį iki 1060° ir 1250°, kylant temperatūrai (125–200) K ruože, kai puslaidininkio skylučių koncentracija N atitinkamai yra 5∙1019 m–3 ir 1020 m–3. Giroelektriniuose p-GaAs bangolaidžiuose HE11 bangų silpimo koeficientas didėja, didinant skylučių koncentraciją, bet anizotropinio dielektriko sluoksnis mažina bangų silpimą. Todėl, kuriant temperatūra valdomus giroelektrinius bangų fazės keitiklius, tikslinga naudoti bangolaidžius su mažesnės koncentracijos skylutėmis ir jautriu temperatūrai anizotropinio dielektriko sluoksniu.

Se presenta un análisis de desempeño de conmutadores de microondas compuestos, de una entrada y una salida (SPST), diseñados con diodos p-i-n tipo masa con diferentes tipos de materiales semiconductores para las bandas de frecuencia Ku y Ka. Las dos configuraciones de conmutadores compuestos más comunes son aquellos con diodos p-i-n ubicados en diseños serie-paralelo y serie-paralelo-serie (TEE) y aquí son analizados utilizando materiales semiconductores de Si, GaAs, GaN-WZ, GaN-ZB, GaSb, InP y SiC. Se presenta la metodología utilizada en los cálculos de resistencia serie y capacitancia de unión en los diodos p-i-n con el propósito de calcular los parámetros de desempeño propios de cada dispositivo conmutador. Estos parámetros son pérdida de inserción y aislamiento. Los conmutadores de tipo serie-paralelo, exceptuando el conmutador basado en diodo p-i-n de SiC-6 H, exhiben pérdidas de inserción menores a 0.2 dB y aislamiento hasta 41dB a la frecuencia de operación de 12 GHz. El conmutador diodo p-i-n tipo TEE con base en GaN-ZB tiene la mejor respuesta de pérdida de inserción menor a 0.23 dB y aislamiento hasta 52 dB, a las frecuencias de operación de 12 GHz y 30 GHz. El conmutador compuesto con base en diodo p-i-n de GaSb alcanza el mejor desempeño a la frecuencia de 12 GHz. Los conmutadores de microondas con configuración TEE tienen respuestas satisfactorias para la frecuencia de 30 GHz.

Compounds of the Tl4LnTe3 (Ln-Nd, Sm, Tb, Er, Tm) composition were synthesized by the direct interaction of stoichiometric amounts of thallium telluride Tl2Te elementary rare earth elements (REE) and tellurium in evacuated (10-2 Pa) quartz ampoules. The samples obtained were identified by differential thermal and X-ray phase analyses. Based on the data from the heating thermograms, it was shown that these compounds melt with decomposition by peritectic reactions. Analysis of powder diffraction patterns showed that they were completely indexed in a tetragonal lattice of the Tl5Te3 type (space group I4/mcm). Using the Le Bail refinement, the crystal lattice parameters of the synthesized compounds were calculated.It was found that when the thallium atoms located in the centres of the octahedra were substituted by REE atoms, there occurred a sharp decrease in the а parameter and an increase in the с parameter. This was due to the fact that the substitution of thallium atoms with REE cations led to the strengthening of chemical bonds with tellurium atoms. This was accompanied by some distortion of octahedra and an increase in the с parameter. A correlation between the parameters of the crystal lattices and the atomic number of the lanthanide was revealed: during the transition from neodymium to thulium, therewas an almost linear decrease in both parameters of the crystal lattice, which was apparently associated with lanthanide contraction. The obtained new compounds complement the extensive class of ternary compounds - structural analogues of Tl5Te3 and are of interest as potential thermoelectric and magnetic materials. References1. Berger L. I., Prochukhan V. D. Troinye almazopodobnyepoluprovodniki [Ternary diamond-like semiconductors].Moscow: Metallurgiya; 1968. 151 p. (In Russ.)2. Villars P, Prince A. Okamoto H. Handbook ofternary alloy phase diagrams (10 volume set). MaterialsPark, OH: ASM International; 1995. 15000 p.3. Tomashyk V. N. Multinary Alloys Based on III-VSemiconductors. CRC Press; 2018. 262 p. DOI: https://doi.org/10.1201/97804290553484. Babanly M. B., Chulkov E. V., Aliev Z. S. et al. Phasediagrams in materials science of topological insulatorsbased on metal chalkogenides. Russian Journal ofInorganic Chemistry. 2017;62(13): 1703–1729. DOI:https://doi.org/10.1134/S00360236171300345. Imamaliyeva S. Z., Babanly D. M., Tagiev D. B.,Babanly M. B. Physicochemical aspects of developmentof multicomponent chalcogenide phases having theTl5Te3 structure. A Review. Russian Journal of InorganicChemistry. 2018;63(13): 1703–1724 DOI: https://doi.org/10.1134/s00360236181300416. Asadov M. M., Babanly M. B., Kuliev A. A. Phaseequilibria in the system Tl–Te. Izvestiya Akademii NaukSSSR, Neorganicheskie Materialy. 1977;13(8): 1407–1410.7. Okamoto H. Te-Tl (Tellurium-Thallium). Journalof Phase Equilibria. 2001;21(5): 501. DOI: https://doi.org/10.1361/1054971007703398338. Schewe I., Böttcher P., Schnering H. G. The crystalstructure of Tl5Te3 and its relationship to the Cr5B3.Zeitschrift für Kristallographie. 1989;188(3-4): 287–298.DOI: https://doi.org/10.1524/zkri.1989.188.3-4.2879. Böttcher P., Doert Th., Druska Ch., Brandmöller S.Investigation on compounds with Cr5B3 and In5Bi3structure types. Journal of Alloys and Compounds.1997;246(1-2): 209–215. DOI: https://doi.org/10.1016/S0925-8388(96)02455-310. Imamalieva S. Z., Sadygov F. M., Babanly M. B.New thallium neodymium tellurides. InorganicMaterials. 2008;44(9): 935–938. DOI: https://doi. org/10.1134/s002016850809007011. Babanly M. B., Imamalieva S. Z., Babanly D. М.,Sadygov F. M. Tl9LnTe6 (Ln-Ce, Sm, Gd) novel structuralTl5Te3 analogues. Azerbaijan Chemical Journal. 2009(1):122–125. (In Russ., abstract in Eng.)12. Imamaliyeva S. Z., Tl4GdTe3 and Tl4DyTe3 –novel structural Tl5Te3 analogues. Physics andChemistry of Solid State. 2020;21(3): 492–495. DOI:https://doi.org/10.15330/pcss.21.3.492-49513. Wacker K. Die kristalstrukturen von Tl9SbSe6und Tl9SbTe6. Z. Kristallogr. Supple. 1991;3: 281.14. Doert T., Böttcher P. Crystal structure ofbismuthnonathalliumhexatelluride BiTl9Te6. Zeitschrift für Kristallographie - Crystalline Materials. 1994;209(1):95. DOI: https://doi.org/10.1524/zkri.1994.209.1.9515. Bradtmöller S., Böttcher P. Darstellung undkristallostructur von SnTl4Te3 und PbTl4Te3. Zeitschriftfor anorganische und allgemeine Chemie. 1993;619(7):1155–1160. DOI: https://doi.org/10.1002/zaac.1993619070216. Voroshilov Yu. V., Gurzan M. I., Kish Z. Z.,Lada L. V. Fazovye ravnovesiya v sisteme Tl-Pb-Te ikristallicheskaya struktura soedinenii tipa Tl4BIVX3 iTl9BVX6 [Phase equilibria in the Tl-Pb-Te system andthe crystal structure of Tl4BIVX3 and Tl9BVX6 compounds].Izvestiya Akademii nauk SSSR. Neorganicheskiematerialy. 1988;24: 1479–1484. (In Russ.)17. Bradtmöller S., Böttcher P. Crystal structure ofcopper tetrathallium tritelluride, CuTl4Te3. CuTl4Te3.Zeitschrift für Kristallographie - Crystalline Materials.1994;209(1): 97. DOI: https://doi.org/10.1524/zkri.1994.209.1.9718. Bradtmöller S., Böttcher P. Crystal structure ofmolybdenum tetrathallium tritelluride, MoTl4Te3.Zeitschrift für Kristallographie – Crystalline Materials.1994;209(1): 75. DOI: https://doi.org/10.1524/zkri.1994.209.1.7519. Babanly M. B., Imamalieva S. Z., Sadygov F. M.New thallium tellurides with indium and aurum.Chemical Problems (Kimya Problemlәri). 2009; 171–174.(In Russ., abstract in Eng.)20. Guo Q., Chan M., Kuropatwa B. A., Kleinke H.Enhanced thermoelectric properties of variants ofTl9SbTe6 and Tl9BiTe6. Chemistry of Materials.2013;25(20): 4097–4104. DOI: https://doi.org/10.1021/cm402593f21. Guo Q., Assoud A., Kleinke H. Improved bulkmaterials with thermoelectric figure-of-merit greaterthan 1: Tl10–xSnxTe6 and Tl10–xPbxTe6. Advanced EnergyMaterials. 2014;4(14): 1400348-8. DOI: https://doi.org/10.1002/aenm.20140034822. Bangarigadu-Sanasy S., Sankar C. R., SchlenderP., Kleinke H. Thermoelectric properties of Tl10-xLnxTe6, with Ln = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Hoand Er, and 0.25<x<1.32. Journal of Alloys andCompounds. 2013;549: 126–134. DOI: https://doi.org/10.1016/j.jallcom.2012.09.02323. Shi Y., Sturm C., Kleinke H. Chalcogenides asthermoelectric materials. Journal of Solid StateChemistry. 2019; 270: 273–279. DOI: https://doi.org/10.1016/j.jssc.2018.10.04924. Piasecki M., Brik M. G., Barchiy I. E., Ozga K.,Kityk I. V., El-Naggar A. M., Albassam A. A.,Malakhovskaya T. A., Lakshminarayana G. Bandstructure, electronic and optical features of Tl4SnX3(X= S, Te) ternary compounds for optoelectronicapplications. Journal of Alloys and Compounds.2017;710: 600–607. DOI: https://doi.org/10.1016/j.jallcom.2017.03.28025. Reshak A. H., Alahmed Z. A., Barchij I. E.,Sabov M. Yu., Plucinski K. J., Kityk I. V., Fedorchuk A. O.The influence of replacing Se by Te on electronicstructure and optical properties of Tl4PbX3 (X = Se orTe): experimental and theoretical investigations. RSCAdvances. 2015;5(124): 102173–102181. DOI: https://doi.org/10.1039/C5RA20956K26. Malakhovskay-Rosokha T. A., Filep M. J.,Sabov M. Y., Barchiy I. E., Fedorchuk A. O. Plucinski K. J.IR operation by third harmonic generation of Tl4PbTe3and Tl4SnS3 single crystals. Journal of Materials Science:Materials in Electronics. 2013;24(7): 2410–2413. DOI:https://doi.org/10.1007/s10854-013-1110-927. Isaeva A., Schoenemann R., Doert T. Syntheses,crystal structure and magnetic properties of Tl9RETe6(RE = Ce, Sm, Gd). Crystals. 2020;10(4): 277–11. DOI:https://doi.org/10.3390/cryst1004027728. Bangarigadu-Sanasy S., Sankar C. R., Dube P. A.,Greedan J. E., Kleinke H. Magnetic properties ofTl9LnTe6, Ln = Ce, Pr, Tb and Sm. Journal of Alloys andCompounds. 2014;589: 389–392. DOI: https://doi.org/10.1016/j.jallcom.2013.11.22929. Arpino K. E., Wasser B. D., and McQueen T. M.Superconducting dome and crossover to an insulatingstate in [Tl4]Tl1-xSnxTe3. APL Materials. 2015;3(4):041507. DOI: https://doi.org/10.1063/1.491339230. Arpino K. E., Wallace D. C., Nie Y. F., Birol T.,King P. D. C., Chatterjee S., Uchida M., Koohpayeh S.M., Wen J.-J., Page K., Fennie C. J., Shen K. M.,McQueen T. M. Evidence for topologically protectedsurface states and a superconducting phase in [Tl4](Tl1-xSnx)Te3 using photoemission, specific heat, andmagnetization measurements, and density functionaltheory. Physical Review Letters. 2014;112(1): 017002-5.DOI: https://doi.org/10.1103/physrevlett.112.01700231. Niu C., Dai Y., Huang B. et al. Natural threedimensionaltopological insulators in Tl4PbTe3 andTl4SnTe3. Frühjahrstagung der Deutschen PhysikalischenGesellschaft. Dresden, Germany, 30 Mar 2014 – 4 Apr2014.32. Imamalieva S. Z. Phase diagrams in thedevelopment of thallium-REE tellurides with Tl5Te3structure and multicomponent phases based on them.Overview. Kondensirovannye sredy i mezhfaznye granitsy =Condensed Matter and Interphases. 2018;20(3): 332–347.DOI: https://doi.org/10.17308/kcmf.2018.20/57033. Jia Y.Q. Crystal radii and effective ionic radii ofthe rare earth ions. Journal of Solid State Chemistry.1991; 95(1): 184-187. DOI: https://doi.org/10.1016/0022-4596(91)90388-X

FABRICACIóN y CARACTERIZACIóN DE SENSORES DE GAS NATURAL (GN) y GAS LICUADO DE PETRóLEO (GLP), BASADOS EN NANOPARTíCULAS DE ZNO FABRICATION AND CARACTERIZATION OF NATURAL GAS (NG) AND LIqUEFIED PETROLEUM GAS (LPG) SENSORS, BASED ON ZNO NANOPARTICLES Robert Paria S, Alcides López M, José Solís V. Facultad de Ciencias, Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Rímac, Lima, Perú Dirección de Investigación y Desarrollo, Instituto Peruano de Energía Nuclear, Av. Canadá 1470, San Borja, Lima DOI: https://doi.org/10.33017/RevECIPeru2010.0004/ RESUMEN Se ha estudiado la influencia de la radiación gamma en una suspensión coloidal de ZnO. Un primer coloide de ZnO se preparó a partir del Zn(CH3COO)2.2H2O, LiOH.H2O y alcohol etílico, mientras que el segundo se preparó a partir del Zn(CH3COO)2.2H2O, NaHO y alcohol propílico. Los coloides de ZnO, fueron irradiados a 30, 50, 75 y 100kGy. Estos coloides irradiados se caracterizaron por Microscopía Electrónica de Transmisión (MET) y Espectroscopía UV-Vis. Se fabricaron películas de ZnO por la técnica spray-pirólisis a partir de los coloides irradiados; estas películas se caracterizaron por difracción de rayos X (DRX). Para evaluar las propiedades eléctricas, se fabricaron películas de ZnO sobre substratos de alúmina impreso con electrodos de oro y este sistema nos sirvió como sensor de gas. El estudio de la dependencia de la conductancia con la temperatura en presencia de aire, revela que la conductividad eléctrica de los sensores varía en función a la composición cristalina, temperatura de operación y la dosis a la cual han sido irradiados los coloides. Diversos patrones de respuesta han sido hallados cuando los sensores son expuestos a Gas Natural (GN) y Gas Licuado de Petróleo (GLP), respuestas típicas de sensores semiconductores tipo n, tipo p y duales han sido encontrados. Palabras clave: Oxido de zinc, coloide, nanopartículas, radiación gamma, sensor de gas. ABSTRACT We have studied the influence of gamma radiation in a colloidal suspension of ZnO. A first ZnO colloid was prepared from Zn(CH3COO) 2.2H2O, LiOH.H2O and ethyl alcohol, while the second was prepared from Zn(CH3COO) 2.2H2O, NaHO and propyl alcohol. The ZnO colloids were irradiated at 30, 50, 75 and 100 kGy. These irradiated colloids were characterized by Transmission Electron Microscopy (TEM) and UV-Vis spectroscopy. ZnO films were produced by spray-pyrolysis technique from irradiated colloids, these films were characterized by X-ray diffraction (XRD). To evaluate the electrical properties of ZnO films, these films were fabricated on alumina substrates with gold electrodes printed and the system served us as gas sensor. The study of the dependence of the conductance with temperature in air, shows that the electrical conductivity of the sensors varies depending on the crystalline composition, operating temperature and the dose at which colloids have been irradiated. Different response patterns were found when the sensors are exposed to Natural Gas (NG) and Liquefied Petroleum Gas (LPG), typical responses of n-type, duals and p-type semiconductor sensors have been found. Keywords: Zinc oxide, colloid, nanoparticles, gamma radiation, gas sensor.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Neste trabalho apresentamos medidas de fotocondutividade, decaimento da fotocondutividade persistente, resistência em função da temperatura em amostras de AlxGa1-xAs de gap direto e indireto, dopadas com Si. Comparamos as teorias de Brooks-Herring e Takimoto, ambas referentes ao espalhamento por impurezas ionizadas, e sua aplicabilidade para nosso material. Interpretamos a presença de um estado de energia intermediário nos cálculos da energia de ativação baseado nos resultados de concentração de elétrons livres em função da temperatura .como devido ao defeito D-. Nos resultados de decaimento da fotocondutividade persistente no intervalo de 80 - 100K, contamos com a contribuição do espalhamento por dipolos e propomos o par d+ - VAS- como os responsáveis pela formação destes dipolos e conseqüente melhoria do ajuste da simulação numérica.
In this work, we show results of photoconductivity, decay of persistent photoconductivity, resistance x temperature in Si doped direct and indirect bandgap AlxGa1-xAs. We compare Brooks-Herring and Takimoto theories, both in reference to ionized impurity scattering applied to our material. We interpret the intermediate state in our calculation of activation energy as a D- defect. In the numerical simulation of decay of persistent photoconductivity in the range 80-100 K, we propose the dipole pair d+ - VAS- responsible for the fitting improvement, when the dipole scattering is taken into account.

Estruturas semicondutoras com dopagem planar são sistemas de considerável interesse tanto para a a pesquisa básica como para a aplicação em dispositivos. Neste trabalho caracterizamos estruturas semicondutoras com dopagem planar tipo n ou p, utilizando técnicas de espectroscopia ótica tais como fotoluminescencência (PL) e fotoluminescência-excitação (PLE). As amostras foram crescidas com a técnica de Epitaxia por Feixe Molecular (BEM, Molecular Beam Epitaxy) no Laboratório de Novos Materiais Semicondutores (LNMS) do IFUSP, com exceção das amostras com dopagem planar tipo p que foram crescidas nos laboratórios do Departamento de Física da Universidade Federal de Minas Gerais. Investigamos as propriedades eletrônicas de super-redes de GaAs com dopagem planar de silício, em função da concentração dos átomos dopantes, mantendo-se fixa a distância entre os planos de dopagem. Através da comparação de nossos resultados experimentais com os de cálculos autoconsistentes da estrutura eletrônica das super-redes, identificamos a origem de todas as emissões observadas nos espectros de PL. As emissões principais (denominada bandas B) foram identificadas como oriundas do processo de recombinação radiativa dos portadores do gás bidimensional de elétrons (2DEG) com buracos fotogerados na banda de valência. Outras emissões (denominadas bandas A) foram associadas com o processo de recombinação dos elétrons do 2DEG com impurezas de Carbono. Analisamos também amostras de poços quânticos de InGaAs/GaAs com dopagem planar de Silício. Nestes sistemas, devido à presença de impurezas (que atuam como centros de espalhamento) e variações na composição da liga de InGaAs (que dão origem à localização de buracos), transições com e /ou sem conservação de quase-momento envolvendo estados de buraco estendidos e/ou localizados constituem os possíveis processos de recombinação radiativa entre os elétrons do 2DEG e os buracos fotogerados. Neste trabalho, investigamos os processos de recombinação dos elétrons do 2DEG com os buracos gerados por excitação ótica comparando a forma de linha dos espectros experimentais e teóricos de PL. Estruturas semicondutoras de GaAs contendos um único plano de átomos de Berílio (dopagem tipo p ) também foram analisadas neste trabalho. Os resultados de nossas investigações evidenciam a existência de um potencial fotoinduzido, que confina os elétrons fotogerados. O processo de formação deste potencial é discutido neste trabalho.
Delta-doped semiconductor structures are systems of considerable interest for basic research and device applications. In this work, we performed the characterization of n or p-type semiconductor structures, using spectroscopic tecniques as photoluminescence (PL), photoluminescence-excitation (PLE) and selective photoluminescence (SPL). The samples were grown by Molecular Beam Epitaxy (BEM) at LNMS (Laboratório de Novos Materias Semicondutores) of IFUSP anda t Physical Department of UFMG. The electronic structure of Silicon delta-doped GaAs super-lattices with different donor concentrations in the delta-doped layer and a fixed distance between adjacent Si-doped layers was investigated. Though the comparison o four experimental results with the superlattices electronic structure calculated self-consistently we identified the origino f all observed in PL spectra structures. The principal emissions (denominated as bands B) are due to recombination of two-dimensional electron gás (due to delta doping) with photocreated holes in Valence band. Other spectral features (denominated as bands A) were associated with recombination of two dimensional electron gás and Carbon impurity. We analyzed PL spectra of InGaAs/GaAs quantum well samples with Silicon delta doping. In this systems recombination of electrons from two-dimensional gas with photocreated holes through the transitions with or without quase-momentum conservation were observed in PL spectra. Comparing experimental and theoretical lineshape, we are able to determine optical transitions in which holes in localize dor extended states took part. Localization of holes in Valence band is due to fluctuations in dopant distribution in the delta-doped layer. Moreover, GaAs with Beryllium delta doping (p-type) were analyzed in this work . Results o four investigation shown the existence of a photoinduced potential, which confine photocreated electrons in strutures of this type. Formation processo f this potential is discussed in this work.

En esta tesis se estudió la reacción de reducción de oxígeno (RRO) sobre electrodos de óxido de Ti modificado con Pt, en una solución de 0,010M HClO4 a 25°C. El óxido de Ti fue crecido potenciodinámicamente sobre un sustrato de vidrio/Ti (electrodo vidrio/Ti/TiO2). Se empleó la técnica de electrodeposición sobre el sustrato de vidrio/Ti previo al crecimiento del óxido, con el método de potencial constante y a diferentes tiempos de deposición (1 ≤ td ≤ 10 segundos). La mejor respuesta electroquímica se obtuvo con el electrodo de Ti/Pt/TiO2 (td = 10 segundos), que indicó un potencial de inicio de la RRO de 0,86V vs ENH (electrodo normal de hidrógeno). Los resultados obtenidos por voltamperometría cíclica revelan la estabilidad del óxido de Ti en presencia del Pt, bajo las condiciones experimentales establecidas en la presente tesis.
This thesis studies the oxygen reduction reaction (ORR) on Ti oxide electrodes modified by Pt in 0.010 M HClO4 at 25°C. The anodic oxide was potentiodynamically grown from glass/Ti substrates (glass/Ti/TiO2 electrode). Pt was electrodeposited on glass/Ti before the anodic oxide growth at constant potential and at deposition times (1 ≤ td ≤ 10 seconds). The highest electrochemical activity was obtained for Ti/Pt/TiO2 (td = 10 seconds) electrodes, with an ORR-current onset of 0.86V vs. NHE. The results obtained from cyclic voltammperometry showed Ti oxide remains stable in presence of Pt, under the specific experimental conditions reported in these studies.

Abstract The transistor structure of memory devices and other cutting-edge semiconductor devices has become extremely minute and complicated owing primarily to advances in process technology and employment of three-dimensional structures. Among the various approaches to improve the device performance and functionality, optimizing the carrier distribution is considered to be quite effective. This study focuses on scanning nonlinear dielectric microscopy (SNDM), a capacitance-based scanning probe microscopy technique. First, to evaluate SNDM's potential for high-resolution measurement, the most commonly used metal coated tip with a tip radius of 25 nm was used to measure a quite low-density impurity distribution. Then, after confirming that the SNDM's S/N ratio was sufficiently high for the smaller probe tip, an ultra-fine diamond probe tip with a nominal tip radius of lesser than 5nm as an SNDM probe tip to measure sub-20 nm node flash memory cell transistors was employed. Successful results were obtained and are reported.