Propriedades óticas e elétricas de dicalcogenetos de metais de transição sobre talco

• Ano de defesa: 2022
• Autor(a) principal: Prando, Gabriela Augusta
• Orientador(a): Gobato, Yara Galvão
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de São Carlos; Câmpus São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• Palavras-chave em Português: Dicalgogenados de metais de transição 2D; Heteroestrutura de van der Waals; Talco; Magneto-ótica; Spin-vale; Efeitos excitônicos; FET
• Palavras-chave em Inglês: Transition metal dichalcogenide; Van der Waals heterostructure; Talc; Magneto-optics; Spin-valley; Excitonic effects; FET
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/16184

Two-dimensional (2D) systems have attracted great attention in the last years, for fundamental physics and in potential applications as optoelectronic devices. There is a great interest in transition metal dichalcogenides (TMDs) due to their direct gap for monolayer, which makes them optically active, with strong spin-valley and excitonic effects. In this work, we explore the use of talc dielectrics as a potentially clean alternative substrate to hexagonal boron nitride (hBN). We a result, we have observed several emission peaks associated with excitonic complexes, including "dark" trions (DT) and phonon replicas of DT. We have performed magneto-photoluminescence studies on high-quality monolayer WS2/talc at low temperature, under high magnetic fields (up to 30T) applied perpendicular to the monolayer plane. The g-factors of the emission peaks were extracted, and the nature of the observed peaks was discussed in detail. In addition, we fabricated field-effect devices (FET) based on MoSe2/talc and MoS2 /talc. Our devices have shown small hysteresis, which does not depend strongly on the sweep rate, and negligible leakage current. In general, our experimental results suggest that talc is a promising material for protecting van der Waals (VdW) heterostructures to explore fundamental physics and for use in optoelectronics.