Within the Inorganic Materials Science (IMS) group, my postdoctoral research focuses on the fabrication of Ferroelectric Tunnel Junctions (FTJs) by Pulsed Laser Deposition (PLD) and lithography processes.
Typically, FTJs are composed of two metallic electrodes separated by a thin insulating ferroelectric layer. In these devices, the current is perpendicular to plane (CPP) and the transfer of electrons between electrodes is realized through the quantum mechanical tunneling effect. Modifying the polarization direction of the ferroelectric layers modifies the potential landscape felt by tunneling electrons, and since tunneling depends exponentially on the barrier height, it results in a drastic change in the tunnel current measured across the heterostructure. This effect is also called the tunneling electroresistance (TER).
In the simplest case, FTJs have two possible polarization direction resulting in two possible device states (ON/OFF). More recently, several groups demonstrated the possibility to continuously tune the device state between the ON and OFF states. As a result, FTJs can be classified as memristive electrical components and are promising candidates to be used in brain inspired neuromorphic devices.
Specifically, my work is carried within the ULPEC project.
“The goal of ULPEC is to develop a microsystem that is natively brain-inspired, connecting an event-based camera to a dedicated Spiking Neural Network* enabled by memristive synapses. This technology should then be used for cases such as the vision and recognition of traffic events (signs, obstacles like other cars, persons, etc.) which is a major challenge for autonomous and computer assisted driving in the transport and car manufacturing sector.”