CAREER: Development of Strain-Engineered AlGalnN Heterostructures for Electronic Device Applications

The focus of this CAREER project is to study and exploit polarization-induced electric fields in AlGaInN-based heterostructures for the development of strain-engineered electronic devices. These devices offer the potential to further expand the performance range of GaN-based electronics to higher frequency and power. Metalorganic vapor phase epitaxy (MOVPE) will be used for epitaxial growth of group III-nitrides in this program. An in-situ optical technique will be developed to probe the evolution and magnitude of thin film stress and strain during heterostructure growth. Alternative nitrogen sources for MOVPE growth will be investigated as a potential route to improving the quality of indium-containing alloys. The techniques and tools will be used to fabricate strain-engineered AlGaN/InGaN/AlGaInN high electron mobility transistor structures. Post-growth characterization (x-ray diffraction, transmission electron microscopy, photoluminescence, Hall measurements) will be combined with real time stress measurements to study stress relaxation and its impact on the microstructural and electrical properties of the heterostructures. Device fabrication and testing will be carried out in collaboration with government and industrial device development groups to provide a pathway for rapid evaluation and transfer of this technology into device and systems applications.

The educational goals of the project are closely integrated to the research. A virtual MOVPE laboratory will be developed and used in course assignments to provide a novel learning tool that connects material properties with processing conditions in an intimate and interactive fashion. Additional educational activities include undergraduate and graduate curriculum development, undergraduate research opportunities, and outreach to young women.