# Materials analysis and focused ion beam nanofabrication of topological insulator Bi2Se3

## TL;DR

This study investigates how focused ion beam milling affects the structure of Bi2Se3 topological insulator nanomaterials, demonstrating its potential for precise nanodevice fabrication despite induced defects.

## Contribution

It provides detailed analysis of ion beam effects on Bi2Se3, combining microscopy techniques to assess structural changes and demonstrating fabrication possibilities.

## Key findings

- Amorphous regions form after ion beam milling.
- Sidewalls of nanowires remain largely intact.
- Crystalline regions persist at wire edges.

## Abstract

Focused ion beam milling allows manipulation of the shape and size of nanostructures to create geometries potentially useful for opto-electronics, thermoelectrics, and quantum computing. We focus on using the ion beam to control the thickness of Bi2Se3 and to create nanowires from larger structures. Changes in the material structure of Bi2Se3 nanomaterials that have been milled using a focused ion beam are presented. In order to characterize the effects of ion beam processing on the samples, we use a variety of techniques including analytical transmission electron microscopy and atomic force microscopy. The results show that while part of the material remains intact after shaping, amorphous regions form where the beam has been used to thin the sample. For wires created by thinning the material down to the substrate, the sidewalls of the wires appear intact based on diffraction images from samples cut at an angle, but thin crystalline regions remain at the wire edges. Even with the resulting defects, focused ion beam milling shows promise for directly fabricating intricate nanodevices of Bi2Se3.