The present book deals with the synthesis and characterization of Germanium (Ge) nanocrystals prepared by using various deposition methods, annealing processes and swift heavy ion irradiation. Even though different methods have been used to prepare Ge nanocrystals, researchers are looking for more compact and versatile synthesis methods for various industrial applications. Here, we have used Atom Beam Sputtering (ABS), RF sputtering and ion implantation for initial depositions. Subsequently these as-deposited samples were annealed at various temperatures using normal furnace annealing, rapid thermal annealing (RTA), microwave annealing and irradiated with swift heavy ions of various energies and fluences for crystallization. Advantages and limitations of these techniques have been discussed in detail.