Influence of temperature and wavelength on the switchable photovoltaic response of a BiFe0.95Mn0.05O3 thin film

TL;DR

This study investigates how temperature and wavelength affect the switchable photovoltaic response of BiFe0.95Mn0.05O3 thin films, revealing defect-related states and mechanisms behind the photovoltaic effects.

Contribution

It provides new insights into the mechanisms of switchable photovoltaic effects in doped BiFeO3 thin films, highlighting the roles of defect states and depolarizing fields.

Findings

Wavelength dependence linked to in-gap states from Mn doping

High open-circuit voltage of 2.5V observed

Temperature response rules out electromigration and Schottky barriers

Abstract

Photovoltaic (PV) response of epitaxial BiFe0.95Mn0.05O3 thin film grown by pulsed laser deposition has been investigated on a broad range of temperature. Wavelength dependent photovoltaic effect shows the contribution of in gap level states most likely connected to the manganese doping on the B-site of the perovskite unit cells and presence of defects (Bi and O vacancies). The temperature dependent response of the PV response rules out electromigration and/or Schottky barriers as dominant mechanisms. This is corroborated with the observed switchable photovoltaic effect that can be explained either by the depolarizing field or bulk photovoltaic effect. In addition the PV response shows strong correlation with the low temperature polaronic like conduction mechanism and high open circuit voltage (2.5V) is detected in the investigated vertical capacitive geometry.