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Description
III-As (III-Al, Ga, In) nanowires (NWs) are considered promising nanostructures for electronics and power generation. Because of their nanoscale diameter, NWs sustain elastic strains up to 10%. This allows to control electronic properties of the NWs by elastic strains. For III-As NWs a 2% mechanical deformation changes photoluminescence position by 290 meV[1] or changes NW conductivity by four orders of magnitude[2,3]. Non-zero piezoelectric coefficients along NW growth axis (111) in zinc blende and wurtzite NWs allows to enhance characteristics of electronic devices. Thus, several electromechanical effects can be studied in III-As NWs: piezoelectric effect, piezoresistive effect, surface piezoresistive effect.
In this work, electromechanical effects in III-As NWs were studied by measuring of I-V curves on single NWs grown on a substrate by a conductive atomic force microscopy (AFM). Strain in NWs was induced by either bending of NW by an AFM probe or by a NW growth on lattice mismatched substrates. Different directions of a NW deformation by the probe (along the NW axis and a lateral bending) allowed to separate piezoelectric and piezoresistive effects. Study of InGaAs NWs with different In-content, where position of the surface Fermi level pinning is controlled by a composition, allowed to reveal a contribution from a surface piezoresistive effect[3]. Analysis of the I-V curves measured for GaAs NWs grown on a Si substrate demonstrated the presence of an fixed charge at the interface, thereby affecting the solar efficiency[4].
This work is supported by Presidential Grant МК-1543.2020.2
[1] G. Signorello, et al., Nano Letters 13, 917 (2013).
[2] G. Signorello, et al., Nano Letters 17, 2816 (2017).
[3] P.A. Alekseev, et al., Nano Letters 19, 4463 (2019).
[4] P.A. Alekseev, et al., Micromachines 11, 581 (2020).
| Speaker Country | Russia |
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