2D ENGINE targets new 2D materials phases that do not exist in Nature in bulk but that can be engineered by synthetic techniques in thin film form. The new 2D phases emerge from their 3D polar parent materials with the wurtzite structure and stabilize below a critical thickness (a few ML) as a result of surface energy minimization, adopting a planar non-polar hexagonal (h) BN-like structure. The new materials exhibiting sp2 hybridization are expected to have the stability of graphene but also possess a finite energy gap that makes them useful for (opto)electronic devices. h-AlN 2D dielectric as well as h-GaN and h-SiC 2D semiconductors are targeted with the aim to fabricate functional electronic and photonic devices, first as a means to validate the quality of these materials at the highest possible level, second to show that the new 2D phases could have an impact addressing urgent needs in digital and Si photonics technologies. Moreover, 2D ENGINE aims to show new functionalities such as nanoscale ferroelectricity produced by twisted bilayer h-AlN or h-BN which can lead to ultra-low power ferroelectric tunnel junction memristors for in-memory computing.
To implement the objectives, we will base our growth methodology on liquid metal catalyst (LMCat) substrates to achieve seamless merging of small islands to larger-area single crystals in the mm scale. High-sensitivity synchrotron XRD, surface analytical techniques, Raman spectroscopy and radiation-mode optical microscopy will be employed for real time (operando) monitoring of growth and for the unambiguous identification of the new 2D phases at the atomic scale supported by atomistic simulations and AI-assisted data analysis. The necessary process modules will be developed with an emphasis on robotic-arm-assisted direct separation, layer twisting and transfer in order to assemble the device layer stacks for further processing of nano-scaled 2D transistors and integrated 2D LED/waveguide systems.