Building on work published over the past few years, a research team at the University of Vienna led by Toma Susi has now used the advanced electron microscope Nion UltraSTEM100 to move single silicon atoms in graphene with truly atomic precision.
The researchers recorded nearly 300 controlled jumps. Additional to extended paths or moving around a single hexagon made of carbon atoms in graphene, a silicon impurity could be moved back and forth between two neighboring lattice sites separated by one tenth-billionth of a meter, like flipping an atomic-sized switch. In principle, this could be used to store one bit of information at record-high density.
The direct manipulation of individual atoms in materials using scanning probe microscopy has been a seminal achievement of nanotechnology. Recent advances in imaging resolution and sample stability have made scanning transmission electron microscopy a promising alternative for single-atom manipulation of covalently bound materials. Pioneering experiments using an atomically focused electron beam have demonstrated the directed movement of silicon atoms over a handful of sites within the graphene lattice. Researchers have now achieved a much greater degree of control, allowing them to precisely move silicon impurities along an extended path, circulating a single hexagon, or back and forth between the two graphene sublattices. Even with manual operation, the manipulation rate is already comparable to the state-of-the-art in any atomically precise technique. They further explore the influence of electron energy on the manipulation rate, supported by improved theoretical modeling taking into account the vibrations of atoms near the impurities, and implement feedback to detect manipulation events in real time. In addition to atomic-level engineering of its structure and properties, graphene also provides an excellent platform for refining the accuracy of quantitative models and for the development of automated manipulation.
Nanoletters – Electron-Beam Manipulation of Silicon Dopants in Graphene

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Scalability is definitely the drawback of any atomically precise top-down manipulation technique. There are ways to create multiple parallel beams, but currently no way have each be focused enough to target single atomic sites.
Scalability is definitely the drawback of any atomically precise top-down manipulation technique. There are ways to create multiple parallel beams but currently no way have each be focused enough to target single atomic sites.
No, it does require graphene from some source, but this is no problem these days.
No it does require graphene from some source but this is no problem these days.
Good point. Perhaps they can produce very many electron beams all at once focused at different positions. But since the atoms would be very close together you would have to worry about interference. Bob Clark
Good point. Perhaps they can produce very many electron beams all at once focused at different positions. But since the atoms would be very close together you would have to worry about interference. Bob Clark
I’m puzzled by the terminology. I would think constructing a desired molecule or nanomachine by positioning individual atoms would be called a bottom-up approach.
I’m puzzled by the terminology. I would think constructing a desired molecule or nanomachine by positioning individual atoms would be called a bottom-up approach.
For the terminology what matters is the direction of control: in bottom-up, chemical components self-assemble in a controlled manner from the bottom up, creating larger structures. In top-down, we use large instruments to manipulate matter on the atomic level from the top down. I believe the source of the terms is this: https://foresight.org/Updates/Briefing2.php
Could it be used to increase the size of the graphene sample? The video shows silicon atoms being moved around within the interior of the graphene. But could an extra carbon atom be moved around to attach to the edge of the graphene and could this be repeated to increase the size of the graphene?
For the terminology what matters is the direction of control: in bottom-up chemical components self-assemble in a controlled manner from the bottom up creating larger structures. In top-down we use large instruments to manipulate matter on the atomic level from the top down. I believe the source of the terms is this:https://foresight.org/Updates/Briefing2.php
Could it be used to increase the size of the graphene sample? The video shows silicon atoms being moved around within the interior of the graphene. But could an extra carbon atom be moved around to attach to the edge of the graphene and could this be repeated to increase the size of the graphene?
6.022 x10^23 atoms in 12 grams of carbon. Making anything one atom at a time is going to take a very long time.
6.022 x10^23 atoms in 12 grams of carbon. Making anything one atom at a time is going to take a very long time.
The silicon atoms were moved around on graphene. But could the technique be used to make graphene or nanotubes? Bob Clark
The silicon atoms were moved around on graphene. But could the technique be used to make graphene or nanotubes? Bob Clark
For the terminology what matters is the direction of control: in bottom-up, chemical components self-assemble in a controlled manner from the bottom up, creating larger structures. In top-down, we use large instruments to manipulate matter on the atomic level from the top down. I believe the source of the terms is this:
https://foresight.org/Updates/Briefing2.php
Could it be used to increase the size of the graphene sample? The video shows silicon atoms being moved around within the interior of the graphene. But could an extra carbon atom be moved around to attach to the edge of the graphene and could this be repeated to increase the size of the graphene?
I’m puzzled by the terminology. I would think constructing a desired molecule or nanomachine by positioning individual atoms would be called a bottom-up approach.
Scalability is definitely the drawback of any atomically precise top-down manipulation technique. There are ways to create multiple parallel beams, but currently no way have each be focused enough to target single atomic sites.
No, it does require graphene from some source, but this is no problem these days.
Good point. Perhaps they can produce very many electron beams all at once focused at different positions. But since the atoms would be very close together you would have to worry about interference.
Bob Clark
6.022 x10^23 atoms in 12 grams of carbon. Making anything one atom at a time is going to take a very long time.
The silicon atoms were moved around on graphene. But could the technique be used to make graphene or nanotubes?
Bob Clark