Realization of high efficiency AlGaInN-based ultraviolet light emitters

摘要

We have reported the growth and characterization of quaternary AlGaInN bulk layer and AlGaInN/InGaN MQWs grown by metal-organic chemical vapor deposition (MOCVD) for high efficiency ultraviolet light-emitting diodes. The inclusion of the small fraction of the indium in AlGaInN layer was found to lead a fewer structural defects and reduction of strain in the layer. From the temperature dependent photoluminescence (TDPL) and time-resolved PL (TRPL), the internal quantum efficiency at 300K was obtained as 60 % for sample grown with quaternary AlGalnN barrier in MQWs and 25 % for the sample with ternary AlGaN barrier. It was resulted that the dominant optical transition in AlGaInN/InGaN MQWs was due to localized exciton recombination and reduction of strain in the QW stack with indium incorporation in the barriers, resulting the longest decay lifetime from quaternary AlGalnN alloys. We measured the optical output power from the UV LED device grown with quaternary AlGalnN barriers.