In the last decade, transition metal dichalcogenides (TMDs) have been intensively synthesized/ studied thus linking their morphological aspect to their physical properties, and consequently leading to the understanding of the possible benefits of defects in such materials. Nevertheless, for future applications, quantifying and identifying defects in TMDs is still a milestone to reach in order to better employ these materials in optoelectronic devices. Raman Spectroscopy has been successfully employed in graphene to quantify punctual or line defects. In this paper, we bombarded monolayer MoSe 2 with He ions and found out the existence of three defect activated Raman bands around 250-300 cm −1 . Density functional theory calculations were employed to obtain the electronic and phonon dispersion bands, making it possible to infer that these bands arise from inter-valley Raman double resonance processes. Interestingly, the same punctual defect model, that allows one to predict the defect concentration at which graphene starts to become amorphous, also works for TMDs. Hence, this work opens the door to the macroscopic quantification of defects in TMDs, which is essential for technological applications.

Este trabalho teve por objetivo o estudo de dicalcogenetos de metais de transição. No decorrer desta atividade foi possível construir o saber para síntese do MoSe2 por Deposição Química a Vapor em substrato de Si/SiO2 sem pré-tratamento. Foi possível obter controle do nível de cobertura do substrato com cristais de MoSe2, além do tamanho e forma de diversas formas cristalográficas em função da pressão parcial de H2. Além disso, realizamos o estudo de defeitos pontuais criados em monocamadas triangulares de MoSe2 por feixe de íons de hélio, possibilitando a identificação de novas bandas de defeitos no espectro Raman desse material.