Transferred Polymer-Encapsulated Metal Electrodes for Electrical Transport Measurements on Ultrathin Air-Sensitive Crystals.

Abstract

Owing to rapid property degradation after ambient exposure and incompatibility with conventional device fabrication process, electrical transport measurements on air-sensitive 2D materials have always been a big issue. Here, for the first time, a facile one-step polymer-encapsulated electrode transfer (PEET) method applicable for fragile 2D materials is developed, which showed great advantages of damage-free electrodes patterning and in situ polymer encapsulation preventing from H2 O/O2 exposure during the whole electrical measurements process. The ultrathin SmTe2 metals grown by chemical vapor deposition (CVD) are chosen as the prototypical air-sensitive 2D crystals for their poor air-stability, which will become highly insulating when fabricated by conventional lithographic techniques. Nevertheless, the intrinsic electrical properties of CVD-grown SmTe2 nanosheets can be readily investigated by the PEET method instead, showing ultralow contact resistance and high signal/noise ratio. The PEET method can be applicable to other fragile ultrathin magnetic materials, such as (Mn,Cr)Te, to investigate their intrinsic electrical/magnetic properties.