[15p-411-1~16] 13.9 Optical properties and light-emitting devices

[15p-411-16] Electro Luminescence Fluctuation of GaN:Eu red LED: Analysis of interactive luminescence processes

〇Masashi Ishii¹, Tomohiro Inaba², Yasufumi Fujiwara² (1.NIMS, 2.Osaka Univ.)

Keywords:fluctuation, rare-earth doped semiconductor, re-excitation

Fluorescence lifetime measurement is a typical method to analyze emission processes. Although mathematically reasonable solution can be obtained by using an attenuation function such as KWW (Kohlausch-Williams-Watts) equation, physical model is frequently difficult to understand from the equation. In order to experimentally probe the actual emission process with physically unclear properties, we have proposed fluctuation measurement techniques. Actually, our previous report on FLF (Fluorescence Lifetime Fluctuation) clarified delayed excitation of emission centers in a new phosphor with strong near UV absorption and bright blue emission. In this study, we attempted to apply a fluctuation measurement to an actual optoelectronic device GaN:Eu LED, namely a promising LED as a GaN-based red light emitter, and found a hidden emission process in which the emission centers in the ground state are re-excited by some process of surroundings (eg. Additional charge transfer from defects to an excitation level).