Electron field emission from tetrahedral amorphous carbon films with multilayer structure

A multilayer structure with alternating metal and semiconductor layers is p roposed to occur in tetrahedral amorphous carbon (ta-C) films prepared by u sing an intermittent layer-by-layer deposition method. In this model, the m ultilayers can be represented as A/B/A/B/.../A/B/A stacks, in which A is co nsidered to be a semimetallic sp(2)-rich graphite-like layer with B being a semiconducting sp(3)-rich diamond-like layer. According to the proposed st ructural model, the electron field emission properties of the ta-C multilay ers that could be modulated by adjusting the total number of layers, layer thickness and sp(3) content of each layer have been predicted. Correspondin gly, three kinds of ta-C multilayers were designed and deposited to confirm this model by enabling us to measure the electron field emission propertie s. Agreement between the prediction and the experimental results has been o bserved. It was found that field emission from ta-C multilayers can be opti mized by changing the number of layers, layer thickness and sp(3) content o f each layer. In our experiments, a threshold electric field (E-th) as low as similar to 5 V/mu m has been obtained for field emission from ta-C multi layers with a total of 20 layers and with a 10 nm layer thickness. (C) 2000 American Institute of Physics. [S0021-8979(00)08411-5].