Wafer Scale Ultra-Clean Van der Waals Heterostructures

Descripción del proyecto

Ensamblado limpio inorgánico de heteroestructuras Van der Waals

Los materiales bidimensionales (M2D) con heteroestructuras de van der Waals (vdW) presentan notables propiedades eléctricas, ópticas, térmicas y mecánicas. Asimismo, tienen una amplia gama de aplicaciones en dispositivos optoelectrónicos y electrónicos delgados como obleas. Actualmente, el proceso de transferencia de M2D desde su sustrato de crecimiento hasta su sustrato designado implica el uso de polímeros orgánicos para soportar M2D. Sin embargo, eso puede provocar una contaminación importante y daños mecánicos en las capas transferidas. Para afrontar esta situación, el proyecto 2D-TRANSFER, financiado por el Consejo Europeo de Investigación, pretende desarrollar una técnica de transferencia completamente inorgánica —y un dispositivo de instrumentación— basado en las necesidades industriales de versatilidad, estándares de calidad y fiabilidad. Esta novedosa técnica no solo permitirá una transferencia sin contaminación, sino que proporcionará una mayor estabilidad mecánica y facilitará métodos alternativos para el ensamblaje de heteroestructuras vdW.

Objetivo

Two dimensional materials (2DM) and their van der Waals (vdW) heterostructures have opened new opportunities to develop
atomically thin electronic and optoelectronic devices with a wide range of functionalities. While thousands of research papers
demonstrate proof-of-concept studies with improved and novel performance using small-scale exfoliated crystals, a number of
challenges still remains when these are attempted to be scaled up on wafer-scale with CVD grown 2DM. One of the key challenges is
the transfer process of 2DM from their growth substrate to another 2DM or a target substrate for intended use. Currently, this process
is performed using organic polymers to support 2DM, which introduces considerable amount of contamination and mechanical
damage to the transferred layers.
We propose to circumvent the existing issues of the transfer process by employing a new technique recently invented in NGI, which
completely avoids use of organic compounds. This approach enables production of heterostructures with perfect interfaces free from
interlayer contamination and correspondingly excellent (opto)electronic behaviour. In addition, eliminating polymeric supports
allows new possibilities for vdW heterostructure fabrication: assembly at temperatures up to 600°C, and in different environments
including ultra-high vacuum (UHV), liquid submersion and improved mechanical stability.
This project will apply our novel approach for wafer-scale use, considering requirements of industrial companies, such as the choice of
2DMs and wafers, quality standards, throughput and reliability. The improved inorganic transfer technology will be then licensed to a
selected 2DM foundry. In addition, we will develop an instrument for wafer-scale 2DM transfer that employs our innovative approach,
which will be made available via spin-out company. Successful completion of the project can bring life to a wide range of industrial
exploitation of 2DM in industrial nanotechnology applications.