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TT: Fachverband Tiefe Temperaturen

TT 3: Topological Insulators (joint session TT/MA)

TT 3.8: Vortrag

Montag, 1. April 2019, 11:30–11:45, Theater

VLS-Growth and characterization of bulk-insulating topological insulator nanowires — •Felix Münning¹, Oliver Breunig¹, Zhiwei Wang¹, Mengmeng Bai¹, Stefan Roitsch², Klaus Meerholz², Thomas Fischer³, Sanjay Mathur³, and Yoichi Ando¹ — ¹Physics Institute II, University of Cologne — ²Institute of Physical Chemistry, University of Cologne — ³Institute of Inorganic Chemistry, University of Cologne, Germany

We report on the growth of Bi₂Te_xSe_3−x and Bi_xSb_2−xTe₃ nanowires and their characterization in terms of morphology, material composition and electronic transport at low temperatures. Growth is performed using the vapour-liquid-solid (VLS) method on Si/SiO₂ substrates decorated with 20-nm Au nanoparticles. Growth parameters such as temperature distribution, mass and ratio of source materials, inert gas flow, pressure and growth time are optimized and the results are examined using scanning and transmission electron microscopy (SEM, TEM) and electron dispersive X-ray spectroscopy (EDX). Devices featuring ohmic contacts to the nanowires are fabricated using electron-beam lithography. Subsequently, the electronic transport properties of the nanowires are measured for their dependencies on temperature, magnetic field and electrostatic gating at temperatures down to 1.7 K.