Pick-and-place transfer of arbitrary-metal electrodes for van der Waals device fabrication

• Main Authors: Xing, Kaijian, McEwen, Daniel, Zhao, Weiyao, Bake, Abdulhakim, Cortie, David, Liu, Jingying, Vu, Thi-Hai-Yen, Hone, James, Stacey, Alastair, Edmonds, Mark T, Watanabe, Kenji, Taniguchi, Takashi, Ou, Qingdong, Qi, Dong-Chen, Fuhrer, Michael S
• Format: Journal Article
• Language: English
• Published: 21-05-2024
• Subjects: Physics - Applied Physics
• DOI: 10.48550/arxiv.2405.12830

Van der Waals electrode integration is a promising strategy to create
near-perfect interfaces between metals and two-dimensional materials, with
advantages such as eliminating Fermi-level pinning and reducing contact
resistance. However, the lack of a simple, generalizable pick-and-place
transfer technology has greatly hampered the wide use of this technique. We
demonstrate the pick-and-place transfer of pre-fabricated electrodes from
reusable polished hydrogenated diamond substrates without the use of any
surface treatments or sacrificial layers. The technique enables transfer of
large-scale arbitrary metal electrodes, as demonstrated by successful transfer
of eight different elemental metals with work functions ranging from 4.22 to
5.65 eV. The mechanical transfer of metal electrodes from diamond onto van der
Waals materials creates atomically smooth interfaces with no interstitial
impurities or disorder, as observed with cross-sectional high-resolution
transmission electron microscopy and energy-dispersive X-ray spectroscopy. As a
demonstration of its device application, we use the diamond-transfer technique
to create metal contacts to monolayer transition metal dichalcogenide
semiconductors with high-work-function Pd, low-work-function Ti, and semi metal
Bi to create n- and p-type field-effect transistors with low Schottky barrier
heights. We also extend this technology to other applications such as ambipolar
transistor and optoelectronics, paving the way for new device architectures and
high-performance devices.