Growth of (In)AlGaN Compound Semiconductors and their Application to 300-nm-Band High-Intensity UV-LEDs

Abstract

We report on the growth and optical properties of (In)AlGaN compound semiconductors for the application of 300-350 nm-band bright ultraviolet (UV) light-emitting diodes (LEDs) or laser diodes (LDs). We demonstrated 230-280-nm UV intense emission from Al(Ga)N/AlGaN multi-quantum wells (MQWs) at 77K. Then we revealed that the 300-nm-band UV emission is considerably enhanced by the In-segregation effect upon introducing approximately 1-5% of In into AlGaN. We fabricated In_x1Al_y1Ga_1-x1-y1N/In_x2Al_y2Ga_1-x2-y2N MQWs with various compositions, and obtained room temperature (R.T.) intense emission in the wavelength of 280-400-nm. The UV emission of the InAlGaN-based MQWs was as strong as that of blue emission from InGaN-based QWs. We also fabricated UV-LEDs using a quaternary InAlGaN active region and achieved high-intensity 345 nm emission under R.T. CW operation.