Abstract
The piezo‐photovoltaic effect has been recently proposed as an analogy of the flexo‐photovoltaic effect in noncentrosymmetric ferroelectrics that are also piezoelectric in nature. It has been demonstrated to boost the photovoltaic performance of ferroelectrics under applied uniaxial mechanical loads. The impact of the piezo‐photovoltaic effect on ferroelectric domains, however, has not yet been studied. In this context, a nanoscale insight into mechanical as well as optomechanical control of domains in a novel bandgap‐engineered ferroelectric, namely—KNBNNO ((K0.5Na0.5)NbO3–2 mol% Ba(Ni0.5Nb0.5)O3−δ), is provided. It is found that the applied mechanical force of 1 μN (pressure: 0.25 GPa) using a scanning probe tip evinces a 67% amplification in piezoresponse in the material, and on removing mechanical load, the material retains 33% higher piezoresponse than the pristine state. Mechanically induced property changes in the material are found to be strongly influenced by light illumination. Applied mechanical stress due to an atomic force microscopy (AFM) tip is highly nonuniform and can induce additional polarization via the flexoelectric effect which further enhances the photovoltaic charge screening.
Highlights
The laser of wavelength 405 nm was selected as in our previous studies we found that it gives a pronounced change in the surface potential which is further compensated by the movement of ferroelectric domains.[30]
The mechanical control of ferroelectric domains is demonstrated in KNBNNO
We show that the ferroelectric domains in KNBNNO can be controlled with the mechanical forces, light, and under the cumulative effect of mechanical force applied using an atomic force microscopy (AFM) tip and the light
Summary
The ferroelectric photovoltaic effect has attracted significant attention in recent years.[1,2] A quest to understand physics[3,4,5]. In this context, we studied ferroelectric domains in bandgapengineered KNBNNO ((K0.5Na0.5)NbO3–2 mol% Ba(Ni0.5Nb0.5) O3Àδ) using customized piezoresponse force microscopy (PFM) with and without light illumination. Based on a nominal change (
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