Ballistic electron emission from quantum-sized nanosilicon diode and its applications

A quantum confinement effect renders silicon a functional wide-gap material with useful functions. For instance, a diode based on nanocrystalline silicon (nc-Si) exhibits characteristic quasi-ballistic emission effects in various media. As means for physical excitation and probing, the applicability to parallel electron beam lithography and high-sensitivity image-pickup has been demonstrated in vacuum. The energetic electron incidence into air and Xe ambient induces negative ion generation by electron attachment into oxygen molecules and vacuum ultraviolet light emission by internal excitation of Xe molecules, respectively. Another effect is that the nc-Si ballistic emitter can supply highly reducing electrons into aqueous and metal-salt solutions without the use of counter electrodes. This is an attractive process that will be applicable to hydrogen generation and thin metal film deposition.

► Nanosilicon diode acts as a planar cold emitter of energetic ballistic electrons.
► The mechanism: multiple-tunneling cascade through nanosilicon dot chain.
► Applications in vacuum: parallel lithography and high-sensitivity image-pickup.
► Applications in gases: negative ion generation in air and VUV emission from Xe.
► Applications in solutions: H2 generation, pH control, and thin film deposition.