Abstract
The paper presents a model of the space charge limited (SCL) electron conduction in a gap with a combination of free space and dielectric solid. The SCL electron current density J is solved numerically to obtain the voltage scaling of J similar to V(G)(n), and n is found to be between n=3/2 (a vacuum gap) and n=2 (a dielectric diode). The dependence of n is calculated as a function of dielectric constant, electron mobility, and the relative length scale between the free space and dielectric solid. The model has been used to explain a recent experiment. (C) 2010 American Institute of Physics. [doi:10.1063/1.3425893]