In this project, we will grow and characterize epitaxial transition metal dichalcogenide (TMD) layered systems for optoelectronics and valleytronics. By combining the growth and optical spectroscopy mutual feedback, we will investigate the effect of the growth conditions (temperature, pressure, growth rate, etc) on the structural and optical properties of different TMD monolayer samples (like MoS2 and MoSe2). Structural characterization of the layer systems will be performed by Atomic Force Microscopy (AFM), Raman spectroscopy and X-ray diffraction. Different optical spectroscopy techniques (micro-photoluminescence and micro-reflectivity) will be employed to detect exciton complexes and defect-related emission in the samples in order to correlate them with the growth conditions and structural characterization. The dependence of the excitonic properties on the dielectric environment, which is detriment for applications, will also be investigated in hybrid systems by transferring the monolayers to different dielectric/piezoelectric substrates. In parallel to the experiments on the epitaxially grown samples, the student will measure the optical properties of mechanically exfoliated systems. Pristine and hexagonal Boron Nitride (hBN) monolayer samples will be fabricated and have their emission properties characterized. This will allow us to test the fabrication of encapsulated systems and at the same time to evaluate the efficiency of the emission of the epitaxial samples.
News published in Agência FAPESP Newsletter about the scholarship: