NANOULOP · Nano-Architectures for Ultrafast Optoelectronics

We propose to fabricate nano-patterned electronic circuits to demonstrate the control of the electronic motion by ultrafast photonic tools. Nanowires and nanosheets will play an important role to build the nano-architecture which allows the direct measurement of the photo current induced by intense, near single-cycle light fields with stable well-defined waveforms. Much attention will be focused on gallium nitride nanowires and titanate nanosheets due to their unique optical and electrical properties and their potential for applications in nanoelectronics. The growth of gallium nitride will be carried out by molecular beam epitaxy. Titanate nanosheets which are wide band gap semiconductor single crystals will be synthesized by exfoliation of layered titanate oxides. Furthermore, assemblies of multilayer films in which the nanosheets are used as building blocks will be fabricated via the layer by layer method. The nanomaterials will be used as bridges between two gold electrodes to build the nano-architectures for attosecond measurements.A valence band electron in a wide band gap solid can find itself promoted by an intense optical field into the conduction band, either by direct photon absorption, multi photon absorption or adiabatic interband tunneling. A second synchronized near single-cycle near-infrared field with well defined waveform will induce an electron momentum asymmetry resulting in a measurable electric current which can be controlled by waveform of the laser pulse. Such operation would enable the detailed understanding of the charge transport processes in direct time-domain, such as dephasing and electron scattering, in low dimensional systems.This project would help not only to demonstrate light-field control of electron motion in low- dimensional systems but also to develop ultrafast electronic technologies like logic circuits performing at optical frequencies in low-dimensional materials.""