High-quality ohmic contacts for broader quasi-two-dimensional materials

Establish whether e-beam-evaporated aluminum oxide sacrificial-mask encapsulation can achieve high-quality ohmic contacts in a broader range of quasi-two-dimensional materials beyond the demonstrated rare-earth tritelluride, tungsten ditelluride, and iron chalcogenide systems.

Background

The paper demonstrates that electron-beam-evaporated aluminum oxide (AlOₓ) can protect air-sensitive materials during fabrication and can function as a sacrificial mask. Thin exposed AlOₓ is removed during tetramethylammonium hydroxide-based photoresist development, allowing direct fabrication of top contacts without separately etching the encapsulation layer. The approach preserves superconducting transport in FeTeₓSe₁₋ₓ devices and is also shown to be nondestructive for RTe₃ and WTe₂ multilayers, with supplementary results for 2H-MoTe₂ and WSe₂.

The authors explicitly identify the broader applicability of the method for producing high-quality ohmic contacts as unresolved. Extending this capability beyond the specific materials and transport devices tested in the paper would be important for integrating a wider range of fragile quasi-two-dimensional materials into electronic and quantum devices.