Functional Oxides with Nitride Buffer Layers for Heteroepitaxial Devices

As conventional memory technologies approach their limit of scalability, there is a quest to find new technologies to replace existing memories. Of the emerging switching phenomena, ferroelectric switching and resistive switching have been considered for this work. Ferroelectricity is a property by which a material develops a spontaneous polarization that can be reversed by and external electric field. Resistive switching, the basis for the novel “memristor” devices, is a property that enables a device switch to a low or high resistance state depending on the magnitude and polarity of the applied voltage. In this work, various nanostructures have been explored to achieve property enhancement in functional oxides. For example, vertically aligned nanocomposite structures consist of two different materials that are simultaneously deposited onto a single substrate, and grow as two distinct phases. Vertically aligned nanocomposite structures offer the advantage of strain tuning through the vertical interfaces between phases. First, to improve the ferroelectric properties of BaTiO3, a conventional ferroelectric material, epitaxial vertically aligned nanocomposite BaTiO3-CeO2 films have been deposited on SrTiO3 substrates. These films exhibit a columnar structure with high epitaxial quality. The films show a similar ferroelectric response as that of pure thin film BaTiO3, but with an improved Curie temperature, despite the incorporation of CeO2. These nanocomposite structures have been replicated on Si substrates using a double buffer layer of SrTiO3/TiN to achieve the eventual integration of these films on Si. No reduction in ferroelectric properties has been observed, but the films again showed an improvement in the Curie temperature. Second, a simple resistive switching device has been demonstrated by the in situ partial oxidation of a TiN film under three different oxidation time periods. The oxidized region consists of near stoichiometric TiO2, and serves as the oxide layer, while the unoxidized TiN serves as the bottom electrode. All films exhibit bipolar resistive switching and all films are forming-free. The forming-free property is attributed to an oxygen deficient TiO2-x layer at the interface between the oxide and nitride regions. Third, ZnO, a piezoelectric, has been selected as another complementary second phase material for BaTiO3. Epitaxial and highly textured vertically aligned BaTiO3-ZnO composite films have been deposited on SrTiO3 substrates and SrTiO3/TiN buffered Si substrates, respectively. Electrical characterization shows that the films grown on both substrates are ferroelectric at room temperature and exhibit similar properties. Composition analysis shows that both the laser fluence and the oxygen partial pressure can modulate the Ba/Ti cation stoichiometry which, in turn, impacts the ferroelectric properties. This is the first demonstration of the vertically aligned nanocomposite of BaTiO3 and ZnO and its silicon based integration. Finally, based on the excellent buffer layer and diffusion barrier properties of TiN for integrating functional oxides on Si, TiN has been applied as a protective layer on metal surfaces. A 500 nm thick TiN layer has been demonstrated to serve as an excellent diffusion barrier in extreme environments

Towards a circular economy: fabrication and characterization of biodegradable plates from sugarcane waste

Bagasse pulp is a promising material to produce biodegradable plates. Bagasse is the fibrous residue that remains after sugarcane stalks are crushed to extract their juice. It is a renewable resource and is widely available in many countries, making it an attractive alternative to traditional plastic plates. Recent research has shown that biodegradable plates made from Bagasse pulp have several advantages over traditional plastic plates. For example, they are more environmentally friendly because they are made from renewable resources and can be composted after use. Additionally, they are safer for human health because they do not contain harmful chemicals that can leach into food. The production process for Bagasse pulp plates is also relatively simple and cost-effective. Bagasse is first collected and then processed to remove impurities and extract the pulp. The pulp is then molded into the desired shape and dried to form a sturdy plate. Overall, biodegradable plates made from Bagasse pulp are a promising alternative to traditional plastic plates. They are environmentally friendly, safe for human health, and cost-effective to produce. As such, they have the potential to play an important role in reducing plastic waste and promoting sustainable practices. Over the years, the world was not paying strict attention to the impact of rapid growth in plastic use. As a result, uncontrollable volumes of plastic garbage have been released into the environment. Half of all plastic garbage generated worldwide is made up of packaging materials. The purpose of this article is to offer an alternative by creating bioplastic goods that can be produced in various shapes and sizes across various sectors, including food packaging, single-use tableware, and crafts. Products made from bagasse help address the issue of plastic pollution. To find the optimum option for creating bagasse-based biodegradable dinnerware in Egypt and throughout the world, researchers tested various scenarios. The findings show that bagasse pulp may replace plastics in biodegradable packaging. As a result of this value-added utilization of natural fibers, less waste and less of it ends up in landfills. The practical significance of this study is to help advance low-carbon economic solutions and to produce secure bioplastic materials that can replace Styrofoam in tableware and food packaging production