[15p-K401-1~15] 15.4 III-V-group nitride crystals

5:15 PM - 5:30 PM JST(8:15 AM - 8:30 AM UTC)English Presentation

[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 Fujimoto^1,3, Yuya Nagata^1,3, 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)

Keywords:

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.