Berlin 2015 – scientific programme
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DS: Fachverband Dünne Schichten
DS 30: Topological insulators: Structure and electronic structure (HL with DS/MA/O/TT)
DS 30.6: Talk
Wednesday, March 18, 2015, 16:15–16:30, ER 270
Wet etch process for HgTe nanostructure fabrication — •Kalle Bendias1, Erwann Bocquillon1, Alex Hughes2, Christoph Brüne1, Hartmut Buhmann1, and Laurens W. Molenkamp1 — 1EP3, Physikalisches Institut, Universität Würzburg — 2Department of Physics, Stanford University
Topological insulators (TI) are a new class of material with outstanding spin properties. Grown in 2d quantum wells HgTe does not only host Quantum Spin Hall edge channels [1][2], but also a giant Rashba splitting [3]. Both could lead to numerous applications in spintronic devices. In order to perform experiments such as spininjection, -probing [3] or quantum point contact collimation [4] a high carrier mobility and i.e. a long ballistic mean free path is essential.
The conventional processing method using ion milling to define the structure strongly affects these surface properties on small microstructures. In this talk the development and results of an alternative lithography etch method using KI:I:HBr as wet etchant are presented. Measurements on microstructures will be shown, indicating comparable mobilities on big and small structures.
[1] Markus König et al., Journal of the Physical Society of Japan 77.3 (2008), S. 031007.
[2] C. Brüne et al., Nature Physics 6.6 (2010), S. 448-454.
[3] J. Hinz et al., Semiconductor science and Technology 21.4 (2006), S 501-506.
[4] L.W. Molenkamp et al., Phys. Rev. B 41, 1274 (1990)