Abstract Topological insulator (Bi 0.06 Sb 0.94 ) 2 Te 3 thin films grown by molecular beam epitaxy have been capped in-situ with a 2 nm Al film to conserve the pristine topological surface states. Subsequently, a shadow mask - structured by means of focus ion beam - was in-situ placed underneath the sample to deposit a thick layer of Al on well-defined microscopically small areas. The 2 nm thin Al layer fully oxidizes after exposure to air and in this way protects the TI surface from degradation. The thick Al layer remains metallic underneath a 3–4 nm thick native oxide layer and therefore serves as (super-) conducting contacts. Superconductor-Topological Insulator-Superconductor junctions with lateral dimensions in the nm range have then been fabricated via an alternative stencil lithography technique. Despite the in-situ deposition, transport measurements and transmission electron microscope analysis indicate a low transparency, due to an intermixed region at the interface between topological insulator thin film and metallic Al.

中文翻译：

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MBE 生长的拓扑绝缘体薄膜上超导接触的模板光刻

摘要 通过分子束外延生长的拓扑绝缘体 (Bi 0.06 Sb 0.94 ) 2 Te 3 薄膜在原位用 2 nm 铝膜覆盖以保持原始拓扑表面态。随后，通过聚焦离子束构建的荫罩原位放置在样品下方，以在明确界定的微观小区域上沉积厚铝层。2 nm 的薄铝层在暴露于空气后会完全氧化，从而保护 TI 表面免于退化。厚铝层在 3-4 nm 厚的天然氧化物层下方保持金属，因此用作（超）导电触点。然后通过另一种模板光刻技术制造了横向尺寸在 nm 范围内的超导体-拓扑绝缘体-超导体结。尽管是原位沉积，