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Field electron emission requiring low electric field represents a big challenge for applications running fiom the realization of field emission planar structures through local cooling by using inverse Nottingham effect [ 11 without surface structuring such as sharp tips or ridges.An approach, called solid-state field-controlled emission (SSE), to control the effective surface bamer for ele'ctron emission by monitoring the space charge value of an ultra-thin layer at the surface ( Fig. 1 a & b), or in other terms to lower the effective surface barrier by modifying the electronic properties of the underneath surface layer ( Fig. 1 (c)), has been proposed and gave stable emission characteristics with low threshold fields [2]. By using now a nanostructure multilayer SSE (Fig. 2), we have added the possibility for a fine control of the space charge value with the presence of sub-bands in the quantum well (Qw) [3]. Figure 1: Solid-statefield-controlled eminer [SSE). [a) The struciure of a single ultra-thin (VrSC) layer SSE. [b) Band edge diagram mod~ications in function of the space charge values. (c) The WO-step electron emission mechanism of the SSE.Figure 2: Nanostructured layers of the cold cathode. (a) Band edge diagram in the absence of an external electricfield (V,,=O); Val and Vb2 are respectively the first and second barriers. The band edge diagram of this nanostructured layer cathode presented then a confine layer of 4 nm limited by aprst barrier Vbl = 0.8 eV at the interface of GaN with Abs Gais N and a second barrier V, = 1.5 eV at the cathode surface of GaN with vacuum. In the absence of applied electric field, El, E2 are the energy levels ofsub-bands inside the quantum well. (b) Schematic structure of the different layers of the cathode within the scanning anode field emission microscopy environment.