Atomic Layer Etching for Nano Device Fabrication We provide an ALE-based method of manufacturing nanostructures with characteristic size below 20nm. This is a new method of nanostructure fabrication using the atomic layer etching process, which is inherently a damage-free etch process. Owing to the etching process’s selectivity to inclined surfaces, which has been recently discovered, the inclined surfaces can be used as a mask and in this way walls of tapered structures, which can be readily fabricated by e.g., dry etching or epitaxial growth, will provide masking during the atomic layer etching process. This is why this process provides access to fabrication of extremely small structures in a very precise and efficient way.