Monolayer h-BeO Formation By Oxidation of Be(0001)

Sammanfattning

Since the discovery of graphene in 2004, there has been intense and continuous research into the possibilities of creating other 2 dimensional (2D) materials. Since then, much progress has been made, resulting in many new metals, semiconductors, and insulators that can fill any number of roles from transistors to solar cells. In this thesis, I discuss hexagonal beryllium oxide (h-BeO) as a potential 2D semiconductor. The samples discussed were characterized using Low Energy Electron Diffraction (LEED), X-ray Photoelectron Spectroscopy (XPS), and Angle-Resolved Photoelectron Spectroscopy (ARPES). Using these techniques, I show that controlled oxygen exposure of a beryllium(0001) sample results in a monolayer 2D honeycomb BeO. Our growth method results in a clear band structure observed by ARPES and the LEED patterns shows clear additional spots and Moiré patterns representing the monolayer oxide. ARPES measurements of the band structure show reasonable agreement with DFT simulations of 1 ML free standing BeO. Photon energy scans of the band structure show that the bands are 2D in nature. The surface bands of the Be(0001) substrate remain after the h-BeO formation, suggesting weak Van der Waals bonding between the oxide and substrate.