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在利用光刻将拓扑绝缘体外延薄膜加工成微米尺寸结构的过程中,所用的各种化学物质会导致薄膜质量的下降.在实验中,通过在钛酸锶衬底上预先光刻出Hall bar形状的凸平台并以此为模板进行拓扑绝缘体(Bi x Sb1-x)2Te3薄膜的分子束外延生长,直接获得了薄膜的Hall bar微器件,从而避免了光刻过程对材料质量的影响.原子力显微镜和输运测量结果均显示该微器件保持了(Bi x Sb1-x)2Te3外延薄膜原有的性质.这种新的微器件制备方法有助于在拓扑绝缘体中实现各种新奇的量子效应,并可推广于其他外延生长的低维系统.
In the process of photolithographically processing a topological insulator epitaxial thin film into a micrometer-sized structure, the various chemicals used lead to a decrease in the quality of the thin film.In the experiment, the Hall bar shape was previously lithographically engraved on a strontium titanate substrate The convex platform was used as the template for the molecular beam epitaxial growth of the topological insulator (Bi x Sb1-x) 2Te3 thin film and the Hall bar micro-device of the thin film was directly obtained, thereby avoiding the influence of the lithography process on the material quality. Atomic Force Microscopy And transport measurements show that the micro-device maintains the original properties of the (Bi x Sb1-x) 2 Te3 epitaxial film.The new micro-device fabrication method can help to realize a variety of novel quantum effects in the topological insulator, And can be extended to other low-dimensional systems that are epitaxy.