Strain Engineering in Ferroelectric-Semiconductor Nanocomposites with Enhanced Bulk Photovoltaic Response

Ferroelectric materials are emerging as promising candidates for the next generation solar cells due to their switchable built-in electric field and above-band-gap photovoltages. Their non-centrosymmetric structure allows to generate bulk photocurrents that can increase the built-in field by orders of magnitude and effectively overcome the Shockley-Quessier limit of single semiconductor heterojunction. However, the wide band-gap and low conductivity of these materials result in unremarkable efficiencies below 1%. While various approaches have been explored, a definitive strategy to enhance the photovoltaic effect without compromising ferroelectric properties remains elusive. In this study, we present the fabrication of two-phase ferroelectric-semiconductor vertically aligned nanocomposites (VANs) using pulsed laser deposition (PLD). We demonstrate the simultaneous enhancement of photovoltaic and ferroelectric properties through precise control of vertical strain imposed by the secondary phase. The impact of deposition parameters and strain on microstructure, electrical, and ferroelectric properties is evaluated before and after selective removal of the secondary phase via wet chemical etching.