《Deep-UV LEDs - physics》.pdf

Invited Paper Deep-UV LEDs: Physics, Performance and Applications R. Gaska and J. Zhang Sensor Electronic Technology, Inc., 1195 Atlas Rd., Columbia, SC 29209, U.S.A. ABSTRACT We present a review of our work on the development and applications of AlInGaN-based deep ultraviolet light emitting diodes (LEDs) with peak emission in the spectral range from 247 nm to 365 nm. The devices demonstrate wall-plug efficiency in excess of 2%, modulation frequency in excess of 200 MHz and very low noise performance. Single wavelength device as well as multi-wavelength high power ultraviolet lamps have been developed for applications in sterilization industry, UV- curing, optical sensors, medical, biomedical and spectroscopic instrumentation. Keywords: III-Nitrides, AlGaN, AlInGaN, ultraviolet LEDs, fluorescence, UV sensors 1. INTRODUCTION Wide and direct energy band of III-Nitride semiconductors make this material system uniquely suited for fabrication of light emitting devices (LEDs and Lasers) with peak emission wavelengths in deep ultraviolet spectral range below 365 nm. Deep ultraviolet (DUV) Light-Emitting Diodes (LEDs) are expected to find numerous applications in air and water sterilization, surface decontamination, optical sensors such as bio-agent detectors, UV curing of polymers, biomedical, medical and analytical instrumentation. Schematics of a typical DUV LED device structure is shown in Fig. 1. Deposition of AlN Pd/Ag/Au + p -AlInGaN