Monolayer h-BeO Formation By Oxidation of Be(0001)
(2025) FYSM34 20251Department of Physics
Synchrotron Radiation Research
- Abstract
- 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... (More)
- 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. (Less)
- Popular Abstract
- It is safe to say that our lives are more integrated with electronics by every day that goes by. From the computers that control our infrastructure to the devices we use for communication between us, there is an ever-growing desire to see them do more with less. The rapid development of new technological advancements made to meet this demand has meant that there is always a need for new ways to construct materials with suitable properties. Today many of these have gone beyond the limits of 3D materials and instead focus on what can be done by stacking ultra-thin sheets of atoms. Of these the most promising are the extreme case of single atom thick sheets, commonly referred to as 2D materials. These materials have seen substantial... (More)
- It is safe to say that our lives are more integrated with electronics by every day that goes by. From the computers that control our infrastructure to the devices we use for communication between us, there is an ever-growing desire to see them do more with less. The rapid development of new technological advancements made to meet this demand has meant that there is always a need for new ways to construct materials with suitable properties. Today many of these have gone beyond the limits of 3D materials and instead focus on what can be done by stacking ultra-thin sheets of atoms. Of these the most promising are the extreme case of single atom thick sheets, commonly referred to as 2D materials. These materials have seen substantial development since the discovery of graphene in the early 2000s which has produced many promising candidates, though many remain theoretical at this time. One such material is the 2D form of beryllium oxide (h-BeO) which shares structure with graphene in that it too looks like a honeycomb. However, it differs in that it consists of a mixture of beryllium atoms and oxygen atoms, while graphene is purely carbon. The differences continue as graphene is a material that is similar to a metal, while h-BeO is more like an insulator. This is a very good thing as 2D insulators are very useful in the construction of nano-electronics. It could in fact be an essential component as part of a certain kind of transistor known as a MOSFET, which relies on having a layer of highly insulating material. In previous studies it has been shown that exposing a beryllium crystal to oxygen will let the oxygen mix with the surface of the beryllium forming layers of oxide that initially have the honeycomb shape we would want. However, these layers after a certain thickness undergo a change in shape where they connect between layers and take on a new shape called a wurtzite structure. For me this is something that was to be avoided, and so limiting the growth to just the first layer became a question of letting just enough oxygen affect the surface. I managed to do this successfully which offers the first step into development of new devices. It also importantly meant that a number of theoretical properties of h-BeO could be measured such as a lower bound of just how insulating it is. Structural properties that have been measured from h-BeO grown in a different manner were also confirmed by my sample. A notable difference to other growth methods was that I also observed interactions between the beryllium surface and h-BeO which may offer a potential avenue for devices with both layers involved. I also observed that the h-BeO layer does not seem very attached to the surface of the beryllium crystal meaning it may be possible to peel this off in the same way once done with graphene. The most important thing to note from my work is that this rather simple method of oxygen exposure can produce controlled layers of the highly insulating 2D structure, h-BeO. Though much work remains in applying this material it may very well be that the future of electronics
may continue to push boundaries by including 2D beryllium oxide layers. (Less)
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http://lup.lub.lu.se/student-papers/record/9212619
@misc{9212619,
abstract = {{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.}},
author = {{Widov, Jonathan}},
language = {{eng}},
note = {{Student Paper}},
title = {{Monolayer h-BeO Formation By Oxidation of Be(0001)}},
year = {{2025}},
}