Estrutura cristalina e eletrônica do CaS: teoria do funcional de densidade aplicada a modelos periódicos

• Ano de defesa: 2014
• Autor(a) principal: Dias, Amanda Fernandes Gouveia
• Orientador(a): Silva, Elson Longo da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Química - PPGQ
• País: BR
• Palavras-chave em Português: Física e química teórica; Sulfeto de cálcio; DFT; Semicondutores; Cálculos teóricos
• Palavras-chave em Inglês: CaS; Semiconductor; Theoretical calculations
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/6583

The incessant search for better materials with diverse applications and increasingly smaller size has been performed by numerous research groups. The calcium sulfide semiconductors have been the focus of study for applications in this field. This semiconductor can be applied in to various devices due to photo- and electroluminescent properties. The technological advances in computational area allowed the improvement in different research fields such as Theoretical Chemistry, which is able to enhance, induce and predict new material properties with potential technological applications. The objective of this project was to apply the Theoretical Chemistry, in order to provide a better understanding of the chemical and structural properties of the calcium sulfide. Models and computer simulations were developed to analyze the electronic and structural properties of this material in crystal and surface level. The results were compared to the experimental data obtained by the microwaveassisted solvothermal method and discussed in terms of band structure, density of states and of charge map. With respect to the lattice parameter and internal coordinates, the theory used show good results, confirming the data obtained experimentally. Theoretical band gap values were also similar to the experimental values and indicated direct transition in all models studied.