Chris Zollner Graduate Student Researcher, Materials Dept., DenBaars Group
AlGaN-based UV-C LEDs grown on SiC and sapphire by MOCVD
HOST: Dr. Tal Margalith
Abstract: AlGaN-based UV-C LEDs are needed for ultraviolet disinfection applications for air, water, and surfaces. The most effective wavelengths for germicidal irradiation (250 nm - 285 nm) require AlGaN active regions with Al molar fractions above 40%, and n- and p-type AlGaN layers with average Al molar fractions of 65% or higher. These ultrawide bandgap alloys present challenges in MOCVD growth, device design, and fabrication technologies which have kept UV-C LED efficiencies below 10% until very recently. In this talk, I will discuss the reasons for the low efficiency of UV-C LEDs compared to blue and white LEDs, and present some approaches to epitaxial growth and device fabrication which improve device efficiency significantly.