Piezoelectric properties of zinc oxide nanowires: anab initiostudy

Abstract

Nanowires made of materials with non-centrosymmetric crystal structures are expected to be ideal building blocks for self-powered nanodevices due to their piezoelectric properties, yet a controversial explanation of the effective operational mechanisms and size effects still delays their real exploitation. To solve this controversy, we propose a methodology based on DFT calculations of the response of nanostructures to external deformations that allows us to distinguish between the different (bulk and surface) contributions: we apply this scheme to evaluate the piezoelectric properties of ZnO [0001] nanowires, with a diameter up to 2.3 nm. Our results reveal that, while surface and confinement effects are negligible, effective strain energies, and thus the nanowire mechanical response, are dependent on size. Our unified approach allows for a proper definition of piezoelectric coefficients for nanostructures, and explains in a rigorous way the reason why nanowires are found to be more sensitive to mechanical deformation than the corresponding bulk material.

Piezoelectric effects and electromechanical theories at the nanoscale

“…51 include molecular dynamics simulations (MDS) [72][73][74][75][76][77][78] and quantum mechanics calculations. [79][80][81] The history of the research advancement in this area has been well reviewed in ref. 10.…”

Thermoelectric transport in ZnO and GaN nanowires

“…It may be noted that, our calculations for N 1D ¼10 7 m À 1 show that PZ phonons dominate up to T $24 K for both screened and unscreened cases. It is also seen that, in the elastic approximation, We have performed calculations for L 43 nm and assume that the PZ constants and effective mass of the electrons are negligibly influenced by the NW size, quantum confinement of carriers and since surface morphology of thinner NWs tend to modify the parameter values and influence the properties [29,30]. In Fig.…”

Introduction to piezoelectricity and electrospun piezoelectric materials and devices

“…With interesting properties and being a lead-free ceramic, zinc oxide (ZnO) presents excellent mechanical properties, piezoelectric response (d33≈ 12.4 and ε'≈ 10.9 [18]) and optical [125,126]. Another characteristic of ZnO is its simple manufacturing in the form of nanoscale fibres, wires and particles [126].…”