Light Power Enhancement of Violet LEDs Using AlGaN-Based Epitaxial Structure

Abstract

The growths of AlN and AlGaN materials were carried out in a home-built metal organic chemical vapor deposition (MOCVD) system. The AlN template was characterized by X-ray diffraction (XRD) and it showed the full width at half magnitude (FWHM) of the x-ray (002) scan rocking curve was only 28 arc seconds, while the FWHM of (102) plane was 252 arc seconds. The results suggested a high quality epitaxial material was obtained. Subsequently, an AlGaN-based violet LED was designed on this template by using AlGaN material as the base. The Al composition of electronic blocking layer (EBL) was optimized. By a quick on-wafer electroluminescence (EL) test, it was demonstrated that the output light intensity of the new structure was at least 15% stronger in comparison to that of the traditional GaN-based violet LED. Finally, fully packaged LEDs were fabricated and the luminous power of the new structure was measured by Spherical integrated system. It was confirmed that a 43% increase of the output power can be obtained.