Towards contacting monolayer TMDC through touch-printed Ga2O3 tunnel barriers
Semonti Bhattacharyya
Transition metal dichalcogenides (TMDCs) are one of the most widely explored group of 2D materials due to various reasons including high on-off ratio in the field-effect geometry, the coupling of spin and valley degree of freedom, and direct bandgap in monolayer limit. However, achieving good electrical contact in these materials has been challenging because of the high Schottky barrier resulting from Fermi-level pinning at the impurity bands created by contact deposition. This issue can be bypassed by inserting an ultrathin layer of insulator between the TMDC and the contact metal as a tunnel barrier, which prevents the formation of defects at the TMDC-metal interface and reduces the barrier due to the dipole effect. Hexagonal boron nitride (hBN) has already been successfully used for this purpose, but growing a large-area, defect-free, ultrathin layer of hBN is tricky. In this work, we attempt to use touch-printed Ga2O3 as the tunnel barrier, which has the capability for making large area (mm-scale) tunnel contacted devices a reality.
As an experimental condensed matter physicist, she has worked extensively on electrical transport properties of topological materials and nanofabrication of 2D materials and their heterostructures. She is highly motivated to explore the various capabilities of these materials for their future applications in low-power electronics.
