Germanium (Ge) played a role of primary importance since the very beginning of the solid-state electronics age. The first transistor, invented at Bell Laboratories in 1947 by William Shockley, John Bardeen, and Walter Brattain, was made with a Ge crystal [1]. On the other hand, the subsequent fast and huge development of microelectronics and integrated circuits was based on silicon (Si). The reasons why Si dominates the microelectronics industry are mostly related to its abundance, low cost and excellent properties of its oxide, the SiO2. Ge has been then mostly applied in the field of infrared photodetectors, due to the lower band gap with respect to Si. In recent years, the use of Ge in microelectronics strongly