Optical properties of transition metal dichalcogenides heterostructures MoS2/WS2 heterojunctions

• Autor(a) principal: Túlio Henrique Lopes Gomes de Castro
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/55856; https://orcid.org/0000-0002-5001-3120
• topic: TMDs; Heterostructures; Monolayers; MoS2; WS2; FRET; Charge transfer; Heteroestruturas semicondutoras; Transferência de carga; Metais de transição

The study of two-dimensional semiconductor heterostructures is of great interest for applications such as the implementation of solar cells and various nanoscale devices such as tunnel field effect transistors. Our work aimed to understand how the interaction between different monolayers of transition metal dichalcogenides in vertical heterostructures affects their optical properties. We are particularly interested in how energy and charge exchange processes take place, and in the formation of interlayer excitons. We studied the photoluminescence dependence on temperature and excitation power in addition to Raman spectroscopy and atomic force microscopy, used to characterize the samples. We find evidence of an energy transfer mechanism between excitons of different layers when they are in direct contact, while in layers separated by a thin h-BN layer, we see a charge transfer via tunneling through this h-BN layer.