[20a-E310-1~10] 15.4 III-V-group nitride crystals

[20a-E310-6] Measurements of Internal Quantum Efficiency in Various InGaN Single Quantum Wells with Different Qualities by Simultaneous Photoacoustic and Photoluminescence Spectroscopy

〇Keito Mori¹, Yuchi Takahashi¹, Atsushi Yamaguchi¹, Susumu Kusanagi², Yuya Kanitani², Yoshihiro Kudo², Shigetaka Tomiya² (1.Kanazawa Inst. of Tech., 2.SONY Corp.)

Keywords:InGaN, Internal Quantum Efficiency, Photoacoustic

Simultaneous measurements of photoacoustic (PA) and photoluminescence (PL) spectroscopy to estimate internal quantum efficiency (IQE) have been improved. Although this method could only be applied to thick films such as epitaxially-grown GaN films so far, the improvement has made it possible to estimate IQE in very thin InGaN single quantum wells (SQWs) with small PA signals. In this study, we have clarified that the main cause of large background noise in PA measurements is vibration of the optical table where a PA cell is located, and we have suppressed the noise by introducing a passive vibration-isolation table. As a result, we have successfully improved the S/N ratio in the PA measurements by more than one order of magnitude. We have also tried demonstrative IQE measurements for various InGaN SQWs samples with different qualities, and have obtained reasonable results.