Executive Summary : | Over the past years, researchers have been exploring perovskite oxide and related materials for multiferroic, optical, ferroelectric, magnetic and photocatalytic properties which are useful for many potential applications such as sensors, storage devices, non-linear optics, piezoelectricity etc. The research on these materials is still continuing. However, the perovskite structured oxide materials are hard to integrate into complementary metal-oxide-semiconductor (CMOS) processes. Ever since the discovery of ferroelectricity in HfO₂ based materials in 2011, the researcher has shifted their focus on HfO₂ based ferroelectric materials to utilize in various potential applications and it is identified as one of the potential candidates in CMOS processing. Hafnium dioxide nanomaterials have high dielectric constant, good chemical stability, and a wide band gap which is suitable for electronics, magneto-electronics, optoelectronics and piezoelectric materials for actuators, and sensors. Apart from these properties, hafnium oxide possesses a multimorphic structure; different phases have their own role, like tetragonal and cubic phase has the main role of obtaining dielectric constant for the ferroelectric property at room temperature. From the literature survey, it is observed that many reported works are mostly on thin films. There are hardly a few reports on chemically synthesized HfO₂ based nanomaterials. In the reported work, many have focused on enhancing the ferroelectric properties by suitable doping on HfO₂. It is found that very few doping elements on HfO₂ have been reported. This means that there are still many scopes for the synthesis of HfO₂ based ferroelectric materials by doping with suitable elements in order to enhance the ferroelectric properties. Thus, considering this fact, this project proposes to synthesize a stabilized form of HfO₂ ferroelectric material and then dope it with a suitable concentration of s/p block elements via a low-cost hydrothermal method. The goal of this project is to develop advanced ferroelectric materials for high performance piezoelectric applications. The Hydrothermal synthesis method is one of the facile and cost-effective processes and is suitable for those materials which have high melting points and pressure and have unstable phases near the melting point. In terms of modification of phase, which is the most significant to get piezoelectric materials, can be done under the control of temperature and pressure. Hafnia has a high melting point so hydrothermal would be the best synthesizing process since nanoparticle formation can be obtained at high temperatures through this process. The expected outcomes of this project are to develop advanced ferroelectric materials with enhanced piezoelectric properties. In the process, it is expected that these materials could be used for a variety of potential applications. |