Field emission measured from nanostructured germanium and silicon thin films

We have prepared nanostructured thin films of germanium and silicon. The films were grown by an ion beam sputtering technique followed by a rapid annealing step using an electron beam annealer. The annealing temperature is a comparatively low 500 °C, resulting in well defined nano-islands on the film surface. Electron field emission has been measured from the surfaces under high vacuum. The threshold electric field value for significant current flow was measured as 2.5 V μm−1 for a silicon thin film which is comparable to other silicon technologies. A value of 0.5 V μm−1 for a germanium thin film represents an order of magnitude improvement for related germanium nanostructured systems.