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Leandro Malard Moreirahttp://lattes.cnpq.br/4670907354729674Bruno Ricardo de CarvalhoPaulo Sérgio Soares GuimarãesAna Paula Moreira BarbozaMatheus Josué de Souza Matoshttp://lattes.cnpq.br/8069564529248118Felipe Menescal Pinto de Medeiros2024-03-12T19:32:08Z2024-03-12T19:32:08Z2023-12-15http://hdl.handle.net/1843/65739In this work, we have investigated the electronic and vibrational properties of WS2 monolayers doped with 0%, 0.4%, and 2.0% concentrations of vanadium (V-WS2), synthesized via Chemical Vapour Deposition. We used various linear and non-linear optical techniques, including Raman spectroscopy, Photoluminescence (PL), Second Harmonic Generation, and Four Wave Mixing, as well as Scanning Probe Microscopy. Fluorescence images indicate the existence of a one-dimensional defect region extending from the vertices to the centers of the triangular flakes of the V-WS2 monolayers, indicating that the dopant concentration is non-homogeneous in these samples. Hyperspectral PL and Raman maps of samples with concentrations of 0%, 0.4%, and 2.0% V-WS2 corroborate the existence of structural non-homogeneity in this same region. The appearance of a new excitonic state around 1.8-1.9 eV is observed in the non-pure samples, attributed to the introduction of vanadium. In addition, for highly doped samples, a negative energy shift of the first-order WS2 vibrational modes is observed at the bisectors of the flakes, indicating that there is a greater accumulation of dopants in these regions, creating a mechanical stress effect in the crystal lattice. Non-linear optics measurements confirm the presence of two emission regions, one resonant with the WS2 exciton and the other resonant with the peak attributed to the introduction of vanadium. Electron Force Microscopy measurements in this region show a more metallic behavior when replacing the tungsten atoms with vanadium. Our results establish linear and non-linear spectroscopy techniques as versatile, strong, and non-destructive tools for characterizing 2D samples doped by metal substitution. Our studies could be useful for improving and efficiently controlling these defects, contributing to the synthesis and large-scale applications of these materials in the near future.Neste trabalho investigamos as propriedades eletrônicas e vibracionais de monocamadas de WS2 dopadas com concentrações de 0%, 0,4% e 2,0% de vanádio (V-WS2), sintetizadas via Deposição Quimica à Vapor. Utilizamos diversas técnicas ópticas lineares e não-lineares, incluindo espectroscopia Raman, Fotoluminescência (PL), Gerador de Segundo Harmônico e Mistura de Quatro Ondas, e, também, Microscopia de Varredura por Sonda. Imagens de fluorescência indicam a existência de uma região de defeitos unidimensional que se estende dos vértices aos centros dos flocos triangulares das monocamadas de V-WS2, indicando que a concentração de dopantes é não-homogênea dessas amostras. Mapas hiperespectrais de PL e Raman em amostras com concentrações de 0%, 0,4% e 2,0% V-WS2 indicam não-homeogenidades estruturais nessa mesma região. É observado o surgimento de um novo estado excitônico em torno de 1,8-1,9 eV nas amostras não puras, atribuído à introdução do vanádio. Além disso, para amostras altamente dopadas, observa-se um desvio negativo de energia dos modos vibracionais de primeira ordem do WS2 nas bissetrizes dos flocos, indicando que há acúmulo maior de dopantes nessas regiões, criando um efeito de tensão mecânica na rede cristalina. Medidas de ótica não-linear confirmam a presença de duas regiões de emissão, uma ressonante com o éxciton do WS2 e outra ressonante com o pico atribuído à introdução de vanádio. Medidas de Microscopia de Força Elétrica nessa região mostram um comportamento mais metálico ao substituir os átomos de tungstênio com vanádio. Nossos resultados estabelecem as técnicas de espectroscopia linear e não-linear como uma ferramenta versátil, forte e não-destrutiva para caracterizar as amostras 2D dopadas por substituição metálica. Nossos estudos podem ser úteis para melhorias e eficiência no controle desses defeitos, contribuindo para a síntese e aplicações destes materiais em grandes escalas num futuro próximo.FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas GeraisengUniversidade Federal de Minas GeraisPrograma de Pós-Graduação em FísicaUFMGBrasilICX - DEPARTAMENTO DE FÍSICAÓptica linearÓptica não-linearMatéria condensada2D materialsNonlinear opticsDefectsSecond harmonic generationFour wave mixingRamanPLMapping defects in vanadium-doped WS2 monolayers by linear and nonlinear opticsMapeando defeitos em monocamadas de WS2 dopadas com vanádio por meio de óptica linear e não linearCartographie des défauts dans les monocouches de WS2 dopées au vanadium par optique linéaire et non linéaireinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFMGinstname:Universidade Federal de Minas Gerais (UFMG)instacron:UFMGORIGINALTese-Mestrado-Felipe-Menescal.pdfTese-Mestrado-Felipe-Menescal.pdfapplication/pdf76679697https://repositorio.ufmg.br/bitstream/1843/65739/1/Tese-Mestrado-Felipe-Menescal.pdf78f9870a63f7cfb652c3f95f4daa5d18MD51LICENSElicense.txtlicense.txttext/plain; charset=utf-82118https://repositorio.ufmg.br/bitstream/1843/65739/2/license.txtcda590c95a0b51b4d15f60c9642ca272MD521843/657392024-03-12 16:32:09.346oai:repositorio.ufmg.br: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ório InstitucionalPUBhttps://repositorio.ufmg.br/oaiopendoar:2024-03-12T19:32:09Repositório Institucional da UFMG - Universidade Federal de Minas Gerais (UFMG)false
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