Refractory Metal Doped Gallium Oxide Sensors for Extreme Environmental Applications

University Of Texas At El Paso, El Paso TX

Investigators

Abstract

Proposal # 1509653 Abstract Title: Refractory metal doped gallium oxide sensors for extreme environment applications Abstract Nontechnical: Currently, an enormous amount of interest exists in the research and development of combustion processes for energy harvesting. Recent analysis shows that by improving coal-based firing/combustion processes in power plants, a cost saving of up to $409 million a year can be achieved. However, in order for this savings and efficiency improvements to occur, sensors and controls capable of withstanding extreme environments such as high temperatures, highly corrosive atmospheres, and high pressures are in critical demand. Besides the economic benefits of reduced costs, controlled combustion can also eliminate the pollutant emissions that are critically impacting our environment, health and energy resources. Optimization of the combustion processes in power generation systems can be achieved by sensing, monitoring and control of oxygen, which is a measure of the completeness of the process and can lead to enhanced efficiency and reduced greenhouse gas emissions. However, despite the fact that there exists a very high demand for advanced sensors for combustion monitoring and control in power generation systems and automobiles, the existing oxygen sensing technologies suffer from poor response and recovery times as well as long-term stability. Technical: The proposed project is intended to investigate the high-temperature oxygen sensors operational to temperatures greater than 700 degrees Celsius in a corrosive atmosphere for application in power generation systems. The overall objective of the research project is to investigate nanostructured gallium oxide (Ga2O3) based sensors for oxygen sensing, where we propose to conduct in-depth exploration of the role of refractory metals (RM) for doping the gallium oxide to enhance the sensitivity, selectivity, stability (3S) criteria) and reliability of such sensors while at the same time keeping device cost economical. The ultimate objective is to design oxygen sensors that combine rapid response, criteria, reliability, and robustness at extreme environments. Specifically, we will focus on engineering the nanostructured Ga2O3 with controlled dopants. The project work will be mainly directed towards fabricating the nanostructured W-Ga2O3, Mo-Ga2O3 and W-Mo-Ga2O3 sensors and gaining a fundamental understanding of dopant-induced structure-composition-electronic property changes on the oxygen sensor performance. The emphasis is to understand changes in the electronic structure of RM-incorporated Ga2O3 sensor as a result of interaction with oxygen. The obvious goal is to study the chemical reactivity of W-Ga2O3, Mo-Ga2O3 and W-Mo-Ga2O3 sensors and quantify the changes in electronic structure so as to derive a structure-property-performance correlation. The proposed study will provide a better understanding of the nanoscale phenomena, adsorption/desorption processes at nanoscale, and size-dependent reactivity to optimize the conditions to enhance the 3S criteria of the oxygen sensors in addition to response time. The results on the nanostructured W-Ga2O3, Mo-Ga2O3 and W-Mo-Ga2O3 sensors are expected to offer exciting opportunities to design and fabricate oxygen sensors with superior performance compared to the existing ones. The project success will, thus, potentially transform the sensor technology and will have a substantial impact on the investigators and students at the University of Texas at El Paso (UTEP), a Hispanic serving minority institution.