ИСТИНА

Cold cathodes based on carbon nanotubes (CNT) are known as efficient sources of electrons which can provide intense and stable electron beams under the action of applied electric field. High efficiency of the field emission (FE) is resulted essentially from high aspect ratio of CNT having micrometer size length at nanometer scale diameter. By having this “wire-like” geometry and one of the highest mechanical strength CNT can sustain considerable elastic deformations induced by the action of the strong electrical ponderomotive forces during FE. The elastic deformations lead to various electromechanical effects which should be taken into account during investigation of field emission. We report here the observation of the electromechanical self-oscillations during emission of electrons from flexible field emitters made of carbon nanotubes. Under the action of a constant voltage applied between a CNT cathode and a flat anode the stable mechanical and emission current oscillations have been observed (Figure 1). The effect was investigated in dependence on geometrical characteristics and voltage applied. We propose an empirical model described by the equations system of the mechanical motion and electrical processes. The model provides a qualitative agreement of the experimental and theoretical results. It is shown that observed phenomenon may be used for the generation of the high frequency electromagnetic waves by using the electromechanical systems with field emitters of nanometer size.