Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany.
Institute for Topological Insulators, Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany.
Nanotechnology. 2023 Mar 6;34(20). doi: 10.1088/1361-6528/acba1d.
We utilize a diffusion-controlled wet chemical etching technique to fabricate microstructures from two-dimensional HgTe/(Hg,Cd)Te-based topological insulators. For this purpose, we employ a KI: I: HBr: HO-based etchant. Investigation of the side profile of the etched heterostructure reveals that HgTe quantum wells protrude from the layer stack as a result of the different etch rates of the layers. This constraint poses challenges for the study of the transport properties of edge channels in HgTe quantum wells. In order to achieve a smoother side profile, we develop a novel approach to the etching process involving the incorporation of a sacrificial design element in the etch mask. This limits the flow of charge carriers to the ions in the electrolyte during the etching process. The simplicity of the method coupled with the promising results achieved thereby should make it possible for the new approach introduced here to be applied to other semiconductor heterostructures.
我们采用扩散控制的湿法化学刻蚀技术，从二维 HgTe/(Hg,Cd)Te 拓扑绝缘体中制造微结构。为此，我们使用了基于 KI：I：HBr：HO 的蚀刻剂。对蚀刻异质结构的侧剖面的研究表明，由于各层的蚀刻速率不同，HgTe 量子阱从层叠结构中突出。这一限制给研究 HgTe 量子阱中边缘通道的输运性质带来了挑战。为了获得更平滑的侧剖面，我们开发了一种新的蚀刻方法，即在蚀刻掩模中加入牺牲设计元素。这限制了在蚀刻过程中电荷载流子流向电解质中的离子。该方法的简单性以及由此获得的有希望的结果，应该使这里引入的新方法能够应用于其他半导体异质结构。
