講演情報
[15p-K401-15]Efficiency Analysis of 230 nm far-UVC LED either grown on Bulk AlN or c-Sapphire as a Function of Quantum-well Numbers
〇(P)Muhammad Nawaz Sharif1, Kohei Fujimoto1,3, Yuya Nagata1,3, Hiromitsu Sakai2, Hiroyuki Yaguchi3, Yukio Kashima4, Muhammad Ajmal Khan1, Hideki Hirayama1 (1.RIKEN, 2.Shin-Etsu Chemical, 3.Saitama University, 4.Marubun Corporation, Chuo, Tokyo)
キーワード：
III-V nitrides semiconductors、AlGaN-based Light emitting Diode
AlGaN-based 230 nm-band far-ultraviolet-C (far-UVC) light sources can safely be used as a germicidal application in both manned as well as unmanned environments against any viruses and microbes including SARS-CoV-2 and bacteria methicillin-resistant Staphylococcus aureus (MRSA). Previously, the 230 nm far-UVC LED grown on c-sapphire with an emission power of 3 mW and the external quantum efficiency (EQE) of 0.4% on the wafer was reported by our Lab, however, the multi quantum-well (MQWs) was not optimized in the context of relaxation ratios. The low relaxation ratio underneath the MQWs is critical for suppressing transverse magnetic (TM)-mode emission and promoting transverse electric (TE)-mode emission. Therefore, herein, we conducted a systemic analysis on optimizing QW numbers for 230 nm far-UVC LED while considering various degrees of relaxation and threading dislocation density (TDD), calculated by SiLENSe. The results show that with a relaxation of 35% and TDD of 1×109 cm,2 assuming to fabricate the LED on the c-sapphire substrate, the carrier injection efficiency (CIE) increases as the number of QWs increases. In contrast, internal quantum efficiency (IQE) decreases due to a reduction in radiative recombination rate. For a 0-degree relaxation referred to as pseudomorphic growth with TDD of 1×104 cm-2, both CIE and IQE increase as the number of QWs are added due to the higher radiative recombination rate and reduced electron leakage.