Transmission Electron Microscope Nanosculpting of Topological Insulator Bismuth Selenide.

We present a process for sculpting BiSe nanoflakes into application-relevant geometries using a high resolution transmission electron microscope. This process takes several minutes to sculpt small areas and can be used to cut the BiSe into wires and rings, to thin areas of the BiSe, and to drill circular holes and lines. We determined that this method allows for sub 10-nm features and results in clean edges along the drilled regions. Using in situ high-resolution imaging, selected area diffraction, and atomic force microscopy, we found that this lithography process preserves the crystal structure of BiSe. TEM sculpting is more precise and potentially results in cleaner edges than does ion-beam modification; therefore, the promise of this method for thermoelectric and topological devices calls for further study into the transport properties of such structures.