**2.2 Electron beam lithography**

Electron beam lithography (EBL) is a lithographic technique that uses a highvoltage accelerated electron beam to directly pattern a substrate without the need of a mask. In this process, the electron beam irradiates a thin layer of electron-sensitive polymer which was previously deposited on the substrate. During the exposure, the polymer (electron beam resist) bonds break and thus after the lift-off process, the appropriate geometric configuration is obtained. This technique has a high resolution, that can be used in nanoscale electronics, optoelectronics and photonics. In our case, in order to contact single nanowires using EBL, the first step is to transfer the nanowires between the metallic interdigitated electrodes. Further, a layer of electron beam resist –polymethyl methacrylate (PMMA) is deposited on the sample. Then, the desired contacts are designed into a CAD program and exposed with the electron beam. After the development process, the Ti and Au or Pt thin films are deposited by RF magnetron sputtering and thermal vacuum evaporation, respectively. Finally, the lift-off process removes the excess metal and the Ti/Au contacts are obtained.
