Nanocrystalline Ge(nc-Ge) single layers and nc-Ge/SiN x multilayers are prepared by laser annealing amorphous Ge(a-Ge) films and a-Ge/SiN x multilayers.The microstructures as well as the electrical properties of laser-crystallized samples are systematically studied by using various techniques.It is found that the optical band gap of nc-Ge film is reduced compared with its amorphous counterpart.The formed nc-Ge film is of p-type,and the dark conductivity is enhanced by6 orders for an nc-Ge single layer and 4 orders for a multilayer.It is suggested that the carrier transport mechanism is dominant by the thermally activation process via the nanocrystal,which is different from the thermally annealed nc-Ge sample at an intermediate temperature.The carrier mobility of nc-Ge film can reach as high as about 39.4 cm2·V-1·s-1,which indicates their potential applications in future nano-devices.
