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Understanding enhanced strain in piezotronic ZnO micro structures using operando Nanofocus diffraction

Thursday (08.06.2017)
11:10 - 11:30 Förde II
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bio magnetic field sensors for medical diagnostics can be designed from magnetostrictive

composite sensors. Here piezoelectric and magnetoelectric properties are

combined to generate a signal in response to a magnetic field. One promising

approach is the additional use of the piezotronic effect, allowing the

sensitivity to be increased by up to three orders of magnitude. Our goal is to understand why the piezotronic

effect results in such a huge increase in sensitivity by studying the lattice strain

in piezotronically active ZnO

micro structures. To achieve this, we used single crystal ZnO micro rods

with an Ohmic and a Schottky contact, fixed on a push-to-pull device to apply a

mechanical stress along the c-axis of the ZnO. Applying a mechanical stress to

the rods, showed that the strain increased in the first 10µm stretched and then

saturated.  For a series of applied

stresses we performed operando piezotronic measurements of the electric

behavior and highly spatially resolved strain maps. X-ray diffraction from the

(004) Bragg reflection showed a surprising factor of two enhancement in the

induced strain in the Schottky barrier region as compared to the pure ZnO rod.

Philipp Jordt
Kiel University
Additional Authors:
  • Dr. Bridget Murphy
    Uni Kiel
  • Dr. Stjepan Hrkac
    Uni Kiel
  • Prof. Dr. Lorenz Kienle
    Uni Kiel
  • Niklas Wolff
    Uni Kiel
  • Prof. Dr. Rainer Adelung
    Uni Kiel
  • Jorit Gröttrup
    Uni Kiel