Wafer Scale Ultra-Clean Van der Waals Heterostructures

Two dimensional materials (2DM) and their van der Waals (vdW) heterostructures have opened new opportunities to developatomically thin electronic and optoelectronic devices with a wide range of functionalities. While thousands of research papersdemonstrate proof-of-concept studies with improved and novel performance using small-scale exfoliated crystals, a number ofchallenges still remains when these are attempted to be scaled up on wafer-scale with CVD grown 2DM. One of the key challenges isthe transfer process of 2DM from their growth substrate to another 2DM or a target substrate for intended use. Currently, this processis performed using organic polymers to support 2DM, which introduces considerable amount of contamination and mechanicaldamage to the transferred layers.We propose to circumvent the existing issues of the transfer process by employing a new technique recently invented in NGI, whichcompletely avoids use of organic compounds. This approach enables production of heterostructures with perfect interfaces free frominterlayer contamination and correspondingly excellent (opto)electronic behaviour. In addition, eliminating polymeric supportsallows new possibilities for vdW heterostructure fabrication: assembly at temperatures up to 600°C, and in different environmentsincluding 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 of2DMs and wafers, quality standards, throughput and reliability. The improved inorganic transfer technology will be then licensed to aselected 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 industrialexploitation of 2DM in industrial nanotechnology applications.