The fabrication of devices made from twisted layers of single-atom-thick graphene is a multistep process involving procedures such as exfoliation, scanning, and stacking. These procedures enable us to isolate monolayer graphene, cut it, and shape it into the device we want. The Atomic Force Microscope (AFM), a high-resolution scanning microscope, plays a key role in this process. In this poster, we will discuss what the AFM is, how it works, and how it is relevant to the innovative fabrication process at our lab. The AFM contains some fundamental components that allow it to image at a nanoscale precision; these include: a cantilever that is affected by changing Van Der Waals forces that bends towards or away from a sample surface, a scanning tip, and a photodiode sensor that senses cantilever movement via a laser and maps the topology of the surface. We will discuss in depth the range of protocols available for use within the AFM. For example, we will outline the difference between contact mode and non-contact mode. More significantly, we will explore the ways in which the lab is innovatively employing the AFM in two distinct processes: scanning and lithography. Currently, the scanning mode on the AFM is a crucial part of the fabrication of twisted multilayer graphene devices as it allows us to qualify the homogeneity of the surfaces we intend to use. Additionally, the AFM is frequently used to slice samples into smaller components in order to build feasible devices. To conclude our discussion of the AFM, we will ultimately outline how the lab plans on using AFM lithography in the near future for nano-patterning on substrates: specifically, to build twisted trilayer graphene quantum dots which are also known as qubits.
"Atomic Force Microscopy in the Assembly of Twisted Multilayer Graphene Devices"
Summer Research Symposium.
Brown Digital Repository. Brown University Library.
Each year, Brown University showcases the research of its undergraduates at the Summer Research Symposium. More than half of the student-researchers are UTRA recipients, while others receive funding from a variety of Brown-administered and national programs and fellowships and go …