Um dos principais desafios no sensoriamento químico e biológico se encontra na detecção de traços de uma dada substância (analito), podendo chegar ao regime de detecção de uma única molécula. Uma forma de se obter este regime de detecção é por meio de análises utilizando a técnica SERS (Surface-Enhanced Raman Spectroscopy) utilizando substratos contendo nanoestruturas metálicas. Neste contexto, um material compósito formado por nanopartículas de ouro localizadas abaixo da superfície de um polímero, o polimetilmetacrilato (PMMA), foi estudado para a utilização como substratos para SERS. Neste trabalho, as nanopartículas foram produzidas através da implantação iônica de baixa energia (49 eV) de ouro em filme fino de PMMA utilizando plasma de arco catódico. O diâmetro médio da nanopartícula para dose de 0,75 x 1016 átomos/cm2 é de (4,25 ± 0,02) nm. Verificou-se que, utilizando esta técnica, as nanopartículas são formadas a uma profundidade de 10 nm abaixo da superfície do polímero. Utilizando esse material como substrato SERS, análises com analito Rodamina 6G (R6G) foram realizadas, e como fonte de excitação, um laser com comprimento de onda de 633 nm. Desta forma, verificou-se a presença dos picos característicos da R6G com concentração de 10 M, nos espectros obtidos, o que não foi possível para um substrato de PMMA sem implantação de ouro. Neste trabalho, pôde-se verificar que a dose utilizada na implantação iônica influencia na intensidade do espectro, de forma que foi observado o aumento da intensidade do sinal SERS com o aumento da dose de implantação no intervalo de 0,64 a 1,02 x 1016 átomos/cm2. Outro efeito observado foi a ocorrência de uma maior intensidade do sinal SERS quando se mantém a camada de PMMA sobre a camada compósita, isto é, sem expor as nanopartículas através da remoção da camada de polímero acima delas. Este comportamento pode ser explicado pelo efeito do intumescimento d solução de R6G, que pode favorecer o aprisionamento das moléculas de R6G na camada de polímero sobre a camada compósita. O melhor resultado foi obtido ao aquecer os substratos a 150 °C por 6 horas. O aquecimento, ao contrário do que se imaginava, não aumenta o tamanho da nanopartícula, mas torna a distribuição de geometrias das nanopartículas mais homogênea, fato que é corroborado através das micrografias obtidas por microscopia eletrônica de transmissão e pelas análises estatísticas. Utilizando a técnica de Espectrofotometria na região Ultravioleta-Visível (UV-Vis) para análise dos substratos que passaram pelo aquecimento, verificou-se um deslocamento de aproximadamente 40 nm do pico de extinção, para a região do vermelho, no espectro do substrato sem a camada de PMMA sobre a camada compósita, além de uma diminuição da extinção. Este resultado indica que a camada de PMMA sobre as nanopartículas influencia as propriedades da camada de PMMA. Além disso os espectros UV-Vis obtidos após o aquecimento dos substratos também corroboram o fato de que há alteração na geometria das nanopartículas. / One of the main challenges in chemical and biological sensing lies in the detection of traces of a given substance (analyte) and can reach the detection regime of a single molecule. One way of obtaining this detection regime is through the Surface-Enhanced Raman Spectroscopy (SERS) technique using substrates containing metal nanostructures. In this context, a composite material formed by gold nanoparticles buried in the surface of a polymer, polymethylmethacrylate (PMMA) has been studied as substrates for SERS. In this work, the nanoparticles were produced by low energy gold ion implantation (49 eV), in thin film of PMMA, using cathodic arc plasma. We found that, using this technique, the nanoparticles are formed 10 nm below the surface of the polymer, with mean nanoparticle diameter of (4.25 ± 0.02) nm at a dose of 0.75 x 1016 atoms/cm2. Using this material as SERS substrate, we performed analyzes with analyte Rhodamine 6G (R6G), and as a source of excitation, a laser with wavelength of 633 nm. In this way, we verified the presence of the characteristic peaks of Rhodamine 6G, with concentration of 10 M, which was not possible for a PMMA substrate without gold implantation. In this work, it was verified that the dose used in the gold ion implantation influences the intensity of the spectrum, so that the increase of the SERS signal intensity was observed with the increase of the implantation dose in the range of 0.64 x 1016 to 1.02 x 1016 atoms/cm2. Another observed effect was the occurrence of a higher intensity of the SERS signal when the PMMA layer was maintained on the composite layer, i.e. without exposing the nanoparticles by removing the polymer layer above them. This behavior can be explained by the swelling effect, which may favor the entrapment of R6G molecules in the polymer layer above the composite layer. The best signal was obtained after annealing the substrates at 150 °C for 6 hours. The annealing does not increase the size of nanoparticles, but makes the distribution of geometries more homogeneous, a fact that is corroborated by the micrographs obtained by transmission electron microscopy and by the statistical analyzes. Using the Spectrophotometry technique in the Ultraviolet-Visible (UV-Vis) region, there was a redshift of approximately 40 nm of the extinction peak of the sample without the PMMA layer above the composite layer, in addition there was a decrease in the extinction. Also, the obtained UV-Vis spectra of the annealed sample corroborate to the fact that there is alteration in the nanoparticles geometry.

Esse trabalho descreve um implantador iônico em termos de sua caracterização e aplicação. O texto está dividido em três capítulos que são apresentados resumidamente a seguir. O primeiro capítulo descreve em detalhes um novo tipo de implantador, denominado implantador invertido. Nesse capítulo é descrito o desenvolvimento e a caracterização do implantador invertido. A otimização de uma parte dos circuitos eletrônicos e o desenvolvimento e construção do restante dos circuitos é dada em detalhes. Uma caracterização do implantador quanto à maximização do feixe iônico é apresentada, onde é realizado um estudo sistemático com a variação de parâmetros como potencial extrator, corrente do canhão de plasma (arco catódico) dentre outros. Finalizando o primeiro capítulo, é apresentado um mapeamento da densidade do feixe iônico no porta amostras do implantador invertido. No segundo capítulo é discutida a neutralidade do feixe iônico do implantador invertido. Um feixe neutro viabiliza implantações em amostras isolantes, sem que haja acúmulo de cargas positivas, o que levaria a amostra a um potencial diferente do planejado. A energia de implantação efetiva foi avaliada estudando os perfis de implantação através de microscopia de força atômica condutiva (AFM-C) e microscopia eletrônica de transmissão (TEM), e comparando com simulações numéricas realizadas pelo programa TRIDYN. Os resultados sugerem que o feixe não é neutro. No terceiro capítulo, o implantador invertido foi utilizado para modificação de superfície de alumina, gerando uma camada de nanocompósito logo abaixo de sua superfície, formada por nanopartículas de titânio na matriz de alumina. A formação dessas nanopartículas se dá espontaneamente e pode ser explicada pela ocorrência de concentração dos átomos metálicos acima do limite de solubilidade no substrato implantado, levando à nucleação e crescimento das nanopartículas metálicas. Caracterização por TEM foi utilizada para a visualização direta das nanopartículas que apresentaram dimensões da ordem de 20 nm. Simulações utilizando o programa TRIDYN foram realizadas, gerando perfis de profundidade dos íons de titânio implantados no substrato de alumina, que mostraram excelente acordo com o perfil em profundidade obtido por RBS (Rutherford Backscattering Spectrometry). Medidas de resistividade da camada compósita foram obtidas, in situ, em função da dose implantada. Utilizando modelos teóricos de percolação foi possível determinar a dose de saturação &#966;0 = 2,2 x 1016 átomos/cm2, que é a dose máxima para a qual o material continua a ser um nanocompósito, e para a condutividade de saturação foi &#966;0 = 480 S/m. A dose de percolação obtida foi &#966;c = 0,84 x 1016 átomos/cm2, que é a dose abaixo da qual o material tem a mesma condutividade que a matriz isolante. O expoente crítico obtido foi t = 1,4 e, como a condição t < 2 é satisfeita, o processo de condutividade se dá devido a percolação, sendo o tunelamento desprezível. / This work describes an ion implanter in terms of characterization and application. The text is divided in three chapters that are briefly presented below. The first chapter describes in detail a new type of implanter called inverted implanter. In this chapter is considered my contribution in the development and characterization of the inverted implanter. The optimization of part of the electronic circuits, and development and construction of other circuits are given in details. A characterization of the implanter by the maximization the ion beam is presented, where is carried out a systematic study through the variation of parameters such as extractor potential, plasma gun current (cathodic arc) and others. Finally, it presents a mapping of the ion beam density at the sample holder of the inverted implanter. The second chapter discusses the neutrality of the ion beam of the inverted implanter. A neutral beam allows implantation into insulating samples without positive charges accumulation, which would lead sample at a different potential than expected. The effective energy evaluation was carried out studying the implantation profiles by conductive atomic force microscopy (AFM-C) and transmission electron microscopy (TEM), and compared with numerical simulations performed by TRIDYN program. The results suggest that the ion beam isn\'t neutral. In the third chapter, the inverted implanter was used for alumina surface modification, generating a nanocomposite layer just below the surface, formed by titanium nanoparticles in alumina matrix. The nanoparticles formation occurs spontaneously and can be explained by the occurrence of metal atom concentration above the solubility limit in the impalnted substrate, leading to nucleation and growth of metal nanoparticles. Characterization by TEM was used for direct visualization of the nanoparticles what presented dimensions of about 20 nm. Simulations using the TRIDYN program were performed, generating depth profiles of titanium ions implanted into the alumina substrate, which showed excellent agreement with the depth profile obtained by RBS (Rutherford Backscattering Spectrometry). Resistivity measurements were obtained from the composite layer, in situ, as function of implanted dose. Using theoretical percolation models, it was possible to determine the saturation dose &#966;0 = 2,2 x 1016 atoms/cm2, that is the maximum dose for which the material remains a nanocomposite, and the saturation conductivity &#966;0 = 480 S/m. The percolation was achieved for dose &#966;c = 0,84 x 1016 atoms/cm2, that is the dose below which the material has the same conductivity as the insulating matrix. The critical exponent obtained was t = 1,4 and, since it satisfies to condition t < 2, the conductivity process is due to percolation, tunneling being negligible.

Esse trabalho descreve um implantador iônico em termos de sua caracterização e aplicação. O texto está dividido em três capítulos que são apresentados resumidamente a seguir. O primeiro capítulo descreve em detalhes um novo tipo de implantador, denominado implantador invertido. Nesse capítulo é descrito o desenvolvimento e a caracterização do implantador invertido. A otimização de uma parte dos circuitos eletrônicos e o desenvolvimento e construção do restante dos circuitos é dada em detalhes. Uma caracterização do implantador quanto à maximização do feixe iônico é apresentada, onde é realizado um estudo sistemático com a variação de parâmetros como potencial extrator, corrente do canhão de plasma (arco catódico) dentre outros. Finalizando o primeiro capítulo, é apresentado um mapeamento da densidade do feixe iônico no porta amostras do implantador invertido. No segundo capítulo é discutida a neutralidade do feixe iônico do implantador invertido. Um feixe neutro viabiliza implantações em amostras isolantes, sem que haja acúmulo de cargas positivas, o que levaria a amostra a um potencial diferente do planejado. A energia de implantação efetiva foi avaliada estudando os perfis de implantação através de microscopia de força atômica condutiva (AFM-C) e microscopia eletrônica de transmissão (TEM), e comparando com simulações numéricas realizadas pelo programa TRIDYN. Os resultados sugerem que o feixe não é neutro. No terceiro capítulo, o implantador invertido foi utilizado para modificação de superfície de alumina, gerando uma camada de nanocompósito logo abaixo de sua superfície, formada por nanopartículas de titânio na matriz de alumina. A formação dessas nanopartículas se dá espontaneamente e pode ser explicada pela ocorrência de concentração dos átomos metálicos acima do limite de solubilidade no substrato implantado, levando à nucleação e crescimento das nanopartículas metálicas. Caracterização por TEM foi utilizada para a visualização direta das nanopartículas que apresentaram dimensões da ordem de 20 nm. Simulações utilizando o programa TRIDYN foram realizadas, gerando perfis de profundidade dos íons de titânio implantados no substrato de alumina, que mostraram excelente acordo com o perfil em profundidade obtido por RBS (Rutherford Backscattering Spectrometry). Medidas de resistividade da camada compósita foram obtidas, in situ, em função da dose implantada. Utilizando modelos teóricos de percolação foi possível determinar a dose de saturação &#966;0 = 2,2 x 1016 átomos/cm2, que é a dose máxima para a qual o material continua a ser um nanocompósito, e para a condutividade de saturação foi &#966;0 = 480 S/m. A dose de percolação obtida foi &#966;c = 0,84 x 1016 átomos/cm2, que é a dose abaixo da qual o material tem a mesma condutividade que a matriz isolante. O expoente crítico obtido foi t = 1,4 e, como a condição t < 2 é satisfeita, o processo de condutividade se dá devido a percolação, sendo o tunelamento desprezível. / This work describes an ion implanter in terms of characterization and application. The text is divided in three chapters that are briefly presented below. The first chapter describes in detail a new type of implanter called inverted implanter. In this chapter is considered my contribution in the development and characterization of the inverted implanter. The optimization of part of the electronic circuits, and development and construction of other circuits are given in details. A characterization of the implanter by the maximization the ion beam is presented, where is carried out a systematic study through the variation of parameters such as extractor potential, plasma gun current (cathodic arc) and others. Finally, it presents a mapping of the ion beam density at the sample holder of the inverted implanter. The second chapter discusses the neutrality of the ion beam of the inverted implanter. A neutral beam allows implantation into insulating samples without positive charges accumulation, which would lead sample at a different potential than expected. The effective energy evaluation was carried out studying the implantation profiles by conductive atomic force microscopy (AFM-C) and transmission electron microscopy (TEM), and compared with numerical simulations performed by TRIDYN program. The results suggest that the ion beam isn\'t neutral. In the third chapter, the inverted implanter was used for alumina surface modification, generating a nanocomposite layer just below the surface, formed by titanium nanoparticles in alumina matrix. The nanoparticles formation occurs spontaneously and can be explained by the occurrence of metal atom concentration above the solubility limit in the impalnted substrate, leading to nucleation and growth of metal nanoparticles. Characterization by TEM was used for direct visualization of the nanoparticles what presented dimensions of about 20 nm. Simulations using the TRIDYN program were performed, generating depth profiles of titanium ions implanted into the alumina substrate, which showed excellent agreement with the depth profile obtained by RBS (Rutherford Backscattering Spectrometry). Resistivity measurements were obtained from the composite layer, in situ, as function of implanted dose. Using theoretical percolation models, it was possible to determine the saturation dose &#966;0 = 2,2 x 1016 atoms/cm2, that is the maximum dose for which the material remains a nanocomposite, and the saturation conductivity &#966;0 = 480 S/m. The percolation was achieved for dose &#966;c = 0,84 x 1016 atoms/cm2, that is the dose below which the material has the same conductivity as the insulating matrix. The critical exponent obtained was t = 1,4 and, since it satisfies to condition t < 2, the conductivity process is due to percolation, tunneling being negligible.

A redistribuição e ativação elétrica dos dopantes tipo n (As e Sb) e tipo p (Ga e In) em Si com excesso de vacâncias foram analisadas. As vacâncias foram geradas por implantação iônica de altas doses de oxigênio ou nitrogênio em alta temperatura, de acordo com procedimentos já estudados. Em seguida foram implantados os dopantes com dose de 5x1014 cm-2 a 20 keV na região rica em vacâncias. Dopagens idênticas foram realizadas em amostras de Si sem vacâncias e em SIMOX. Em seguida foram feitos recozimentos a 1000ºC por 10 s ou 15 min. Os perfis atômicos dos dopantes foram medidos com Medium Energy Ion Scattering e os perfis dos dopantes ativados, com Hall diferencial. A redistribuição e as propriedades elétricas de cada um dos dopantes no Si sem vacâncias foram bastante similares às observadas no SIMOX, porém várias diferenças foram observadas em relação às amostras com excesso de vacâncias. As vacâncias reduziram a ativação elétrica do As e do Sb, mas proporcionaram maior estabilidade da ativação após recozimentos longos. A redistribuição destes dopantes foi infuenciada pelo íon usado na geração das vacâncias, ou seja, nitrogênio ou oxigênio. O oxigênio proporcionou maior dose retida de As e o nitrogênio, maior dose retida de Sb. Já para o Ga e o In, as vacâncias tiveram papel fundamental na sua redistribuição, diminuindo a difusão para fora das amostras e garantindo maior dose retida. A ativação elétrica do Ga e especialmente a do In foram baixas, onde observamos forte influência do íon pré-implantado, principalmente o oxigênio. / The redistribution and electrical activation of n type (As and Sb) and p type (Ga and In) dopants in Si with excess vacancy concentration were analyzed. The vacancies were formed by high dose ion implantation of oxygen or nitrogen at high temperature, following previously studied procedures. Dopants were implanted to a dose of 5x1014 cm-2 at 20 keV in the vacancy rich regions of the samples. Identical doping implantations were performed in bulk Si and SIMOX. Samples were then submitted to thermal annealing at 1000ºC for 10 s or 15 min. The dopants atomic profiles were obtained by Medium Energy Ion Scattering and the active dopant profiles, by differential Hall measurements. The redistribution and the electrical properties of each dopant in bulk Si were similar to those observed in SIMOX, but several differences were observed in the vacancy-rich samples. Vacancies reduced the electrical activation of As and Sb, although the activation was maintained stable after long annealing times. The redistribution of these dopants was, otherwise, dominated by the ion used in the vacancy generation, i.e., nitrogen or oxygen. The presence of oxygen resulted in larger As retained dose, while the presence of nitrogen, in larger Sb retained dose. Regarding the p type dopants, Ga and In, the vacancies played an important role in their redistribution, reducing their out-diffusion and allowing larger retained doses. Ga and especially In electrical activation was low, where strong influence of the pre-implanted ions was observed, especially oxygen.

Abstract not available

In the last years, there is a rise of interest in investigation and fabrication of nanometer sized magnetic structures due to their various applications (e.g. for data storage or micro sensors). Over the last several decades ion beam implantation became an important tool for the modification of materials and in particular for the manipulation of magnetic properties. Nanopatterning and implantation can be done simultaneously using focused-ion beam (FIB) techniques. FIB implantation and standard ion implantation differ in their beam current densities by 7 orders of magnitude. This difference can strongly influence the structural and magnetic properties, e.g. due to a rise of the local temperature in the sample during ion implantation. In previous investigations both types of implantation techniques were studied separately. The aim of the current research was to compare both implantation techniques in terms of structural changes and changes in magnetic properties using the same material system. Moreover, to separate any possible annealing effects from implantation ones, the influence of temperature on the structural and magnetic properties were additionally investigated. For the current study a model material system which is widely used for industrial applications was chosen: a 50 nm thick non-ordered nano-crystalline permalloy (Ni81Fe19) film grown on a SiO2 buffer layer based onto a (100)-oriented Si substrate. The permalloy films were implanted with a 30 keV Ga+ ion beam; and also a series of as-deposited permalloy films were annealed in an ultra-high vacuum (UHV) chamber. Several investigation techniques were applied to study the film structure and composition, and were mostly based on non-destructive X-ray investigation techniques, which are the primary focus of this work. Besides X-ray diffraction (XRD), providing the long-range order crystal structural information, extended X-ray absorption fine structure (EXAFS) measurements to probe the local structure were performed. Moreover, the film thickness, surface roughness, and interface roughness were obtained from the X-ray reflectivity (XRR) measurements. Additionally cross-sectional transmission electron microscope (XTEM) imaging was used for local structural characterizations. The Ga depth distribution of the samples implanted with a standard ion implanter was measured by the use of Auger electron spectroscopy (AES) and Rutherford backscattering (RBS), and was compared with theoretical TRIDYN calculation. The magnetic properties were characterized via polar magneto-optic Kerr effect (MOKE) measurements at room temperature. It was shown that both implantation techniques lead to a further material crystallization of the partially amorphous permalloy material (i.e. to an increase of the amount of the crystalline material), to a crystallite growth and to a material texturing towards the (111) direction. For low ion fluences a strong increase of the amount of the crystalline material was observed, while for high ion fluences this rise is much weaker. At low ion fluences XTEM images show small isolated crystallites, while for high ones the crystallites start to grow through the entire film. The EXAFS analysis shows that both Ni and Ga atom surroundings have a perfect near-order coordination corresponding to an fcc symmetry. The lattice parameter for both implantation techniques increases with increasing ion fluence according to the same linear law. The lattice parameters obtained from the EXAFS measurements for both implantation types are in a good agreement with the results obtained from the XRD measurements. Grazing incidence XRD (GIXRD) measurements of the samples implanted with a standard ion implanter show an increasing value of microstrain with increasing ion fluence (i.e. the lattice parameter variation is increasing with fluence). Both types of implantation result in an increase of the surface and the interface roughness and demonstrate a decrease of the saturation polarization with increasing ion fluence. From the obtained results it follows that FIB and standard ion implantation influence structure and magnetic properties in a similar way: both lead to a material crystallization, crystallite growth, texturing and decrease of the saturation polarization with increasing ion fluence. A further crystallization of the highly defective nano-crystalline material can be simply understood as a result of exchange processes induced by the energy transferred to the system during the ion implantation. The decrease of the saturation polarization of the implanted samples is mainly attributed to the simple presence of the Ga atoms on the lattice sites of the permalloy film itself. For the annealed samples more complex results were found. The corresponding results can be separated into two temperature regimes: into low (≤400°C) and high (>400°C) temperatures. Similar to the implanted samples, annealing results in a material crystallization with large crystallites growing through the entire film and in a material texturing towards the (111) direction. The EXAFS analysis shows a perfect near-order coordination corresponding to an fcc symmetry. The lattice parameter of the annealed samples slightly decreases at low annealing temperatures, reaches its minimum at about ~400°C and slightly rises at higher ones. From the GIXRD measurements it can be observed that the permalloy material at temperatures above >400°C reaches its strain-free state. On the other hand, the film roughness increases with increasing annealing temperature and a de-wetting of the film is observed at high annealing temperatures. Regardless of the material crystallization and texturing, the samples annealed at low temperatures demonstrate no change in saturation polarization, while at high temperatures a rise by approximately ~15% at 800°C was observed. The rise of the saturation polarization at high annealing temperatures is attributed to the de-wetting effect.

This investigation examines band gap engineering of the GaAsN alloy by means of plasma ion implantation. The strong redshift of the alloy's band gap is suitable for telecommunication applications and thus stimulated much interest in recent years. Nitrogen (N) ion implantation into gallium arsenide (GaAs) results in a thin shallow N-rich layer below the surface. However, the violent implantation process also modifies the concentrations of gallium and arsenide. The core of this thesis is a novel method for prediction of the band gap from the conditions in the processing plasma.<p>The first important variable, the number of implanted ions, is obtained from the Lieberman model for the current during high-voltage Plasma Ion Implantation (PII). A review of the model's assumptions is provided as well as a comprehensive discussion of the implantation which includes error boundaries. The predicted and measured ion currents agree within error boundaries. The number of implanted ions can therefore be obtained from the prediction.<p>The distribution of the implanted ions was subsequently explored by simulations such as TRIM and TRIDYN. It was found that the nitrogen content in GaAs is limited by the sputtering of the surface atoms. Furthermore, the content of gallium increases near the surface while the content of arsenic decreases. The predicted ratios of the constituents in the implanted layer is such that the alloy cannot form by ion implantation alone; it could be reconciled by annealing.<p>Preliminary samples were produced and tested for the formation of the GaAsN alloy by Raman spectroscopy. No evidence for bonds between N and either Ga or As was found in the as-implanted samples. The thesis concludes with a discussion of the necessary steps to synthesize the GaAsN alloy.

This investigation examines band gap engineering of the GaAsN alloy by means of plasma ion implantation. The strong redshift of the alloy's band gap is suitable for telecommunication applications and thus stimulated much interest in recent years. Nitrogen (N) ion implantation into gallium arsenide (GaAs) results in a thin shallow N-rich layer below the surface. However, the violent implantation process also modifies the concentrations of gallium and arsenide. The core of this thesis is a novel method for prediction of the band gap from the conditions in the processing plasma.<p>The first important variable, the number of implanted ions, is obtained from the Lieberman model for the current during high-voltage Plasma Ion Implantation (PII). A review of the model's assumptions is provided as well as a comprehensive discussion of the implantation which includes error boundaries. The predicted and measured ion currents agree within error boundaries. The number of implanted ions can therefore be obtained from the prediction.<p>The distribution of the implanted ions was subsequently explored by simulations such as TRIM and TRIDYN. It was found that the nitrogen content in GaAs is limited by the sputtering of the surface atoms. Furthermore, the content of gallium increases near the surface while the content of arsenic decreases. The predicted ratios of the constituents in the implanted layer is such that the alloy cannot form by ion implantation alone; it could be reconciled by annealing.<p>Preliminary samples were produced and tested for the formation of the GaAsN alloy by Raman spectroscopy. No evidence for bonds between N and either Ga or As was found in the as-implanted samples. The thesis concludes with a discussion of the necessary steps to synthesize the GaAsN alloy.

Šio darbo literatūros apžvalgoje aptariami plazmos tipai, plazmos charakteristikos bei sąveika su medžiaga. Aptariama plazminės implantacijos technologija. Trumpai apibūdinama vandens garų plazma ir jos panaudojimas. Apžvelgiama titano oksido struktūra bei jo panaudojimas katalizatorių gamybai, kurie gali būti skirti skaldyti vandens molekules ir gaminti vandenilį. Darbe paaiškinamas magnetroninis nusodinimas bei jo privalumai. Darbo metu buvo oksiduojamas titanas vandens garų plazmoje. Titano oksidacija priklauso nuo daugybės plazmoje vykstančių procesų (adsorbcija, sulaikymas, vakansijų susidarymas ir pan.). Titano oksido panaudojimas yra labai platus dabartiniu metu. Aptariama šio eksperimento technologija bei atliekama oksiduotų titano dangų analizė. SEM, XRD, AES, GDOES analizės metodais buvo tiriama titano dangos oksidacija ir aiškinamas oksidacijos mechanizmas. / Types of plasma, characteristics and plasma interaction with solids are discussed in the literature review of this paper. Also, the plasma immersion ion implantation are described. Water vapour plasma are briefly discussed. Titanium oxide structure and it‘s usage for catalyst which could split water molecules are reviewed. Magnetron deposition are explained in this paper. The titanium film was oxidized by water vapour plasma on experiment. The oxidation of titanium depends on many processes in plasma (adsorption, trapping, formation of oxygen vacancies and etc.). Appliance of titanium oxide is very large in recent times. Experimental technology are discussed and plasma treated films are analysed. Titanium oxidation was analysed by SEM, XRD, AES, GDOES. Oxidation mechanism was explained in this paper.

Doping allows us to modify semiconductor materials for desired properties such as conductivity, bandgap, and / or lattice parameter. A small portion replacement of the highly mismatched isoelectronic dopants with the host atoms of a semiconductor can result in drastic variation of its structural, optical, and / or electronic properties. Here, the term "mismatch" describes the properties of atom size, ionicity, and / or electronegativity. This thesis presents the fabrication of two kinds of highly mismatched semiconductor alloys, i.e., Ge(1-x)Sn(x) and GaAs(1-x)N(x). The structural and optical properties of the prepared Ge(1-x)Sn(x) and GaAs(1-x)N(x) have been investigated. The results suggest an efficient above-solubility doping induced by non-equilibrium methods of ion implantation and ultrashort annealing. Pulsed laser melting promotes the regrowth of monocrystalline Ge(1-x)Sn(x), whereas flash lamp annealing brings about the formation of high quality GaAs(1-x)N(x) with room temperature photoluminescence. The bandgap modification of Ge(1-x)Sn(x) and GaAs(1-x)N(x) has been verified by optical measurements of spectroscopic ellipsometry and photoluminescence, respectively. In addition, effective defect engineering in GaAs has been achieved by flash lamp annealing, by which a quasi-temperature-stable photoluminescence at 1.3 µm has been obtained. / Dotierung ermöglicht es, die Eigenschaften von Halbleitermaterialien, wie Leitfähigkeit, aber auch Bandabstand und / oder Gitterkonstanten gezielt zu verändern. Wenn ein Halbleiter mit einer kleinen Menge unterschiedliche Fremdatome dotiert wird, kann dies in einer drastischen Modifikation der strukturellen, optischen und / oder elektronischen Eigenschaften resultieren. Der Begriff "unterschiedlich" bedeutet hier die Eigenschaften von Atomgröße, Ioniztät und / oder Elektronegativität. Diese Doktorarbeit beschreibt die Herstellung von zwei Arten von stark fehlangepassten Halbleiterlegierungen: Ge(1-x)Sn(x) und GaAs(1-x)N(x). Die strukturellen und optischen Eigenschaften von Ge(1-x)Sn(x) und GaAs(1-x)N(x) wurden untersucht. Die Ergebnisse deuten auf eine effiziente Dotierung oberhalb der Löslichkeit, induziert durch die Nicht-Gleichgewichtsverfahren Ionenimplantation und Ultrakurzzeit-Ausheilung. Gepulstes Laserschmelzen ermöglicht das Nachwachsen von monokristallinem Ge(1-x)Sn(x), während die Blitzlampenausheilung in der Bildung von GaAs(1-x)N(x) hoher Qualität mit Photolumineszenz bei Raumtemperatur resultiert. Die Änderung der Bandlücke von Ge(1-x)Sn(x) und GaAs(1-x)N(x) wurde durch die optischen Methoden der spektroskopischen Ellipsometrie und Photolumineszenz verifiziert. Darüber hinaus konnte in ausgeheiltem GaAs eine quasi-temperaturstabile Photolumineszenz bei 1,3 µm beobachtet werden.