CAREER: Investigating Process-Structure-Property Correlations of Nitrides and Oxides for High Temperature Thermoelectric Applications

学院早期职业发展(CALEAR)计划拨款用于研究用于高温热电发电的具有多种长度尺度结构的纳米结构块状氮化物和氧化物的新加工机制。基本的假设是，多个长度尺度的纳米结构可以通过过程工程来控制，因此可以作为一种有效的方法来调节热电性能，通过解耦电学和热学性能。为了验证这一假设，我们采用了一项综合的实验和理论研究，考察了与加工相关的参数，包括原子尺度、纳米尺度和微尺度结构，以及它们对热电性能的相应影响。氮化镓和氧化锌是这项工作的模型体系，因为它们具有良好的热电性能以及在高温下的机械和化学稳定性。如果成功，这一计划将使一种新的具有成本效益、热稳定和无毒的热电材料能够在高温下回收废弃的能量。在温度通常超过1000K的工业过程中，每年总共产生1500万亿BTU的废热。由于当前技术的工作温度被限制在800K以下，一种新型的、高达1000K的热电材料将对回收这些浪费的能量做出关键贡献。从这个项目中获得的科学可以更广泛地转化为热电、光伏和激光设备的进一步发展。这一职业项目的教育贡献包括在与能源有关的课程中创建跨学科教育和研究单元，加强未被充分代表的学生对科学和工程的参与，以及向K-12年级的学生推广科学和工程事业。

This Faculty Early Career Development (CAREER) Program grant provides funding to investigate new processing mechanisms of nanostructuring bulk nitrides and oxides with multiple length-scale structures for high temperature thermoelectric power generation. The underlying hypothesis is that multiple length-scale nanostructures can be controlled by process engineering and thus be used as an effective method to tune thermoelectric properties by decoupling electrical and thermal properties. To test this hypothesis, an integrated experimental and theoretical study is used to examine the processing-related parameters including atomic-scale, nanoscale, and micro-scale structures and their corresponding effects on thermoelectric properties. Gallium nitride and zinc oxide are the model systems for this work due to their promising thermoelectric properties and mechanical and chemical stability at high temperatures. If successful, this program will enable a new class of cost-effective, thermally stable and nontoxic thermoelectric materials for wasted energy recovery at high temperatures. A total of 1500 trillion BTU/year of waste heat is generated from industrial processes where temperatures typically exceed 1000K. A new class of thermoelectric materials that are robust up to 1000K will make a key contribution to recover this wasted energy since the operational temperature of current technology is limited to below 800K. The science gained from this project can be transformed more broadly into the further development of thermoelectric, photovoltaic, and laser devices. The educational contributions of this CAREER project include creating interdisciplinary education and research modules within energy-related curriculums, enhancing underrepresented students' participation in science and engineering, and outreach to K-12 students to pursue a career in science and engineering.