Tensile strained germanium nanowires measured by photocurrent spectroscopy and X-ray microdiffraction.

Abstract

Applying tensile strain in a single germanium crystal is a very promising way to tune its bandstructure and turn it into a direct band gap semiconductor. In this work, we stress vapor-liquid-solid grown germanium nanowires along their [111] axis thanks to the strain tranfer from a silicon nitride thin film by a microfabrication process. We measure the Γ-LH direct band gap transition by photocurrent spectrometry and quantify associated strain by X-ray Laue microdiffraction on beamline BM32 at the European Synchrotron Radiation Facility. Nanowires exhibit up to 1.48% strain and an absorption threshold down to 0.73 eV, which is in good agreement with theoretical computations for the Γ-LH transition, showing that the nanowire geometry is an efficient way of applying tensile uniaxial stress along the [111] axis of a germanium crystal.

DOI: 10.1021/nl5048219

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Cite this paper

@article{Guilloy2015TensileSG, title={Tensile strained germanium nanowires measured by photocurrent spectroscopy and X-ray microdiffraction.}, author={Kevin Guilloy and Nicolas Pauc and Alban Gassenq and Pascal Gentile and Samuel Tardif and F. Rieutord and Vincent Calvo}, journal={Nano letters}, year={2015}, volume={15 4}, pages={2429-33} }