Boosting Hole Mobility in Coherently Strained [110]-Oriented Ge-Si Core-Shell Nanowires

Journal article (2017)

Authors

S. Conesa Boj Eindhoven University of Technology, QN/Conesa-Boj Lab - AS
A. Li QRD/Kouwenhoven Lab - QuTech Advanced Research Centre , Eindhoven University of Technology
Sebastian Koelling Eindhoven University of Technology
Matthias Brauns University of Twente
Joost Ridderbos University of Twente
T. T. Nguyen University of Twente
M.A. Verheijen Student
P. M. Koenraad Eindhoven University of Technology
F. A. Zwanenburg University of Twente
E.P.A.M. Bakkers Eindhoven University of Technology, QN/Bakkers Lab
Research Group
QN/Conesa-Boj Lab (AS) (TU Delft)
Nanowire Mobility Silicon Germanium Epitaxy Defect-free
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Published Date

12-04-2017

Language

English

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Faculty

Applied Sciences

Department

QN/Quantum Nanoscience

Research Group

QN/Conesa-Boj Lab

Abstract

The ability of core-shell nanowires to overcome existing limitations of heterostructures is one of the key ingredients for the design of next generation devices. This requires a detailed understanding of the mechanism for strain relaxation in these systems in order to eliminate strain-induced defect formation and thus to boost important electronic properties such as carrier mobility. Here we demonstrate how the hole mobility of [110]-oriented Ge-Si core-shell nanowires can be substantially enhanced thanks to the realization of large band offset and coherent strain in the system, reaching values as high as 4200 cm2/(Vs) at 4 K and 1600 cm2/(Vs) at room temperature for high hole densities of 1019 cm-3. We present a direct correlation of (i) mobility, (ii) crystal direction, (iii) diameter, and (iv) coherent strain, all of which are extracted in our work for individual nanowires. Our results imply [110]-oriented Ge-Si core-shell nanowires as a promising candidate for future electronic and quantum transport devices.