Research Projects

The study of tunable ferroelectric thin films for microwave applications has been a topic of interest for decades. However, the reasons behind lower permittivity and tunability in these films are not fully understood. One possible explanation is the formation of depletion layers due to electroding, which can result from oxygen interdiffusion, structural defects, or schottky barriers at the interfaces. Another issue is the presence of strains at the interfaces when films are deposited onto dissimilar substrates, leading to in-plane deformation that modifies permitivity and temperature variation. The iso-valent substituted BTO compounds (BaTi1-xsnxO3, BsnTO) have been studied in recent years but have not been explored in this context. BsnTO compounds offer superior temperature coverage and stability compared to BsT ferroelectrics, making them suitable for this investigation. Negative capacitance (NC) on the application of an electric field has recently gained interest as it can be used to construct steep-slope field-effect transistors (FETs), which could help overcome power scaling issues in semiconductor technology. HfO2-based materials are considered more suitable for this purpose. The proposed project aims to investigate the tunability of ferroelectric properties with temperature and electric field by creating nano-sized ferroelectric thin films and heterostructures with various electrodes and geometries. Lead-free ferroelectrics, primarily BTO and Hafnia-based (HfO2) systems, will be used in the project. systematic investigation with different metal contacts and capacitor geometry will help understand the role of depolarization fields on the tunability of functional properties.