Locating nanowire heterostructures by electron beam induced current

Electron beam induced current (EBIC) in a scanning electron microscope (SEM) was used to identify the positions of heterostructures in InAs/InP nanowires. Composite SEM and EBIC images were used to locate heterostructures and quantum dots in the nanowires, and used in subsequent electron beam lithography to align local gate electrodes to these quantum dots. This has made it possible to use individual and local gates for single heterostructure-nanowires. The observed EBIC contrast is caused by charge separation of the electron-hole pairs generated by the electron beam close to the heterostructures, indicating the presence of band bending. In this article, we concentrate on devices based on nanowires containing heterostructures, but we envisage the use of the technology on any type of nano-sized devices where the precise alignment of contacts to electrically active parts is necessary