Dissertação de Mestrado #690 – Túlio Henrique Lopes Gomes de Castro – 20/01/2023

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 focus in this work was 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 for the characterization of 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.