David Todd Emerson

Milliwatt Power Deep Ultraviolet Light Emitting Diodes Grown on Silicon Carbide

Deep ultraviolet light emitting diode structures with a peak wavelength of 275 nm were grown by metalorganic chemical vapor deposition on (0001) silicon carbide. Despite its strong ultraviolet light absorption, silicon carbide was chosen as a substrate rather than sapphire for its improved thermal conductivity and the potential for vertically conducting devices. An output power of 0.11 mW was observed at 300 mA DC during single device on-wafer testing, and output powers of 2.09 mW at 1.3 A were obtained from a packaged, silicone encapsulated array of five devices. Forward voltages as low as 4.9 V at 20 mA were obtained. The injection profile of Cp2Mg during the p-AlGaN blocking layer was instrumental in the suppression of emission at undesired wavelengths and the realization of peak-to-defect level ratios greater than 100.