Two methods to prepare nanorings/nanoholes for the fabrication of vertical nanotransistors

A self-assembled monolayer of polystyrene (PS) beads is formed on a silicon wafer by spin-coating. After drying at 80 °C, a thin film of metal/oxide is deposited. During the deposition, the PS beads are detached due to forces such as the inner stress induced by plasma sputtering deposition, mechanical vibration, and centrifugal shearing induced by substrate rotation, resulting in nanoring/nanohole formation. Further experiments demonstrate that the PS detachment can be controlled by scanning probe microscopy (SPM) tip manipulation. We believe this is a promising set of processes for fabricating nanodevice structures such as those of vertical nanotransistors, which provides high flexibility for nanocrystal characterizations and application for single-electron devices.