Development of Ferro Photovoltaic Induced Self Powered BiFeO3 based Heterostructure Photodetectors via Spray Pyrolysis Technique

Abstract

Pollution-free and low energy consumption are the essential features of any electronic device that desires further developments to attain a improved sustainable future. In the same way, this is crucial for the commercially accessible photodetectors also. They are mostly made up of Pb-based materials and constantly consume much energy when using external bias voltage. Hence, it is always dependent on batteries. This creates environmental issues because recycling a battery is challenging and cumbersome. To eliminate the need for batteries, self-powered devices are more greeted by researchers. Further, the material used for the photodetector fabrication should be ecofriendly because releasing toxic materials like lead into the environment during material processing and disposal may cause serious health problems. In this context, in the present dissertation, we have fabricated a lead-free self-powered photodetector (SPPD) using BiFeO3 (BFO) perovskite material. BFO is a lead-free multiferroics material that exhibits high transition temperatures such as ferroelectric Curie temperature (TC = 1100 K) and antiferromagnetic Neel temperatures (TN = 640 K), which are substantially above room temperature. However, the BFO perovskite has some drawbacks like high leakage current attributed to oxygen vacancies and the Fe2+ state of iron. This would lead to lower performance of the device. In this regard, the present thesis describes developing high-performance BFO-based self-powered heterojunction photodetectors. First, the oxygen vacancies are decreased by substituting the optimum density of Zr4+ ions dopant at B-site of the BFO nanoparticles. The impedance measurements confirmed that the optimum substitution of Zr4+ ions dopant at Fe site would lessen the oxygen vacancies. Hence, 1.5% Zrdoped BFO nanostructured thin film sample showed the lowest dielectric constant (~79) at 1 kHz due to the filling of oxygen vacancies by Zr4+ ions and displayed a significant photocurrent of ~3.10 mA at 5V. However, for 2.5 % Zr dopant concent