In nanocrystalline silicon (nc-Si) dots interconnected with tunnel oxides, the characteristic electron transport mode appears followed by highly hot electron effects: avalanche photoconduction and quasi-ballistic electron emission. Analysis of the former clarifies that the impact ionization rate in nc-Si dots is considerably higher than in bulk Si. The usefulness of the latter has been confirmed in various media. A typical example of the application in vacuum is the use as the excitation source for parallel electron beam lithography. Another potential is induced by the operation in aqueous and metal salt solutions, where the highly reducing reaction proceeds at the emitter surface. In SiCl4 and GeCl4 solutions, for instance, thin Si and Ge films are deposited without the use of any counter electrodes. Some topics of these effects are discussed here.