Non-linear nanoscale piezoresponse of single ZnO nanowires affected by piezotronic effect

Abstract

ZnO nanowires (NW) as semiconductor piezoelectric nanostructures have emerged as the focus material for applications in energy harvesting, photonics, sensing, biomedical science, actuators or spintronics. The expression of the piezoelectric properties in semiconductor materials is concealed by the screening effect of the available carriers and the piezotronic effect, leading to complex nanoscale piezoresponse signals. Here, we have developed a metal-semiconductor-metal model to simulate the piezoresponse of single ZnO nanowires, demonstrating that the apparent non-linearity in the piezoelectric coefficient arises from the asymmetry created by the forward and reversed biased Schottky barriers at the semiconductor-metal junctions. By directly measuring the experimental I-V characteristics of ZnO NWs with C-AFM together with the piezoelectric vertical coefficient by PFM, and comparing them with the numerical calculations for our model, effective piezoelectric coefficients in the range d33eff ~ 8.6 pm/V -12.3 pm/V have been extracted for ZnO NWs. We have further demonstrated via simulations the dependence nanowire's growth together with a scheme of the NWs growth using the hydrothermal method; experimental details of the PFM and C-AFM measurements.

A Portable and Flexible Self-Powered Multifunctional Sensor for Real-Time Monitoring in Swimming

“…When the humidity increases to 60%, the piezoelectric voltage remains stable because the oxygen vacancies on the surface of the ZnO NWs are occupied by water molecules, forming a thin water film. Then, the shielding effect does not continue to increase with the increasing humidity [ 25 , 42 , 43 , 44 , 45 , 46 , 47 ]. Furthermore, the piezoelectric voltage is not affected by the change in humidity, so the biosensor can be tested and used to monitor a swimmer in water.…”

Recent Advances in Physical Sensors Based on Electrospinning Technology

“…BaTiO 3 has the advantages of excellent piezoelectricity, nontoxicity, and easy synthesis, and its piezoelectricity coefficient is 43 pm V –1 , which is higher than that of pure ZnO (12.3 pm V –1 ) . Therefore, its doping can obtain a higher piezoelectricity performance.…”

“…BaTiO 3 has the advantages of excellent piezoelectricity, nontoxicity, and easy synthesis, and its piezoelectricity coefficient is 43 pm V −1 , which is higher than that of pure ZnO (12.3 pm V −1 ). 80 Therefore, its doping can obtain a higher piezoelectricity performance. The flexible piezoelectric sensor fabricated by the PVDF nanocomposites loaded with 10 wt % BaTiO 3 nanoparticles had a good sensitivity (18.0 V N −1 ) and a good linear relationship between pressure and voltage output.…”

Toward localization in terahertz-operating energy harvesting software-defined metamaterials

“…Prototypical implementations of localization-enabled THz-operating energy-harvesting SDMs will be needed for confirming (or discarding) the insights made in this and potentially future simulation-oriented works. In this direction, pioneering efforts on developing graphene-based antennas [41,74] and transceivers [75], nanoscale energy-harvesters [76,77], as well as SDMs prototypes are worth emphasizing [3,78,79,80,81,82,83].…”