Silicon and germanium are the materials of choice of modern electronics. With increasing complexity and performance of integrated circuits, adding new optical functionalities on the current electronic levels is currently the topic of an intense research.

The goal of this PhD is to probe by means of the photocurrent spectroscopy technique the changes in the absorption coefficient of single germanium nanowires as a function of the doping level and stress state. This study will allow optimizing the conditions for which the direct gap luminescence of Ge is enhanced. In the course of this PhD, previous results will be used to build efficient Ge NW based light emitting devices. As mid term perspectives, this work could lead to the fabrication of germanium based laser sources. This study will allow the candidate to acquire various skills in the field of nanosciences: the nanofabrication of test devices on single nanowires, the optical characterization, the simulation of the absorption and transport properties of the nanowires, and the fabrication of electroluminescent devices.