Philip Chan Graduate Student Researcher, Nakamura Group
University of California, Santa Barbara
Red InGaN-based LEDs with high active region growth temperature
Long wavelength InGaN micro-LEDs are challenging to grow but critical for next generation displays. The low growth temperatures required to produce high indium composition films and large lattice mismatch between the active region and template degrade crystal quality and reduce radiative efficiency. Highly relaxed InGaN buffer layers were grown by MOCVD across 2-inch c-plane sapphire substrates. The buffer layers were relaxed by the in-situ thermal decomposition of an InGaN underlayer during growth. A 75 nm redshift was demonstrated by room temperature photoluminescence of quantum wells regrown on a buffer relaxed by this technique. Full LEDs grown on these buffers with an active region growth temperature of 870 °C have achieved red emission longer than 630 nm and voltage under 2.6 V at 25 Acm-2.