[12a-M111-1~9] 15.7 Crystal characterization, impurities and crystal defects

▲ [12a-M111-8] Cathodoluminescence study on InGaN/GaN multiple quantum shell

〇Wei Yi¹, Jun Chen¹, Jun Uzuhashi¹, Tetsuya Takeuchi², Satoshi Kamiyama², Tadakatsu Ohkubo¹, Takashi Sekiguchi^1,3 (1.NIMS, 2.Meijo Univ., 3.Tsukuba Univ.)

Keywords:GaN, multiple quantum shell, Cathodoluminescnece

For the development of optical devices using core-shell GaN Nanowires (NWs), we propose a systematic characterization technique using cathodoluminescence (CL) and STEM. InGaN/GaN multiple quantum shell (MQS) structures were grown on GaN nanowires by MOCVD (Meijo Univ.). Five parts of MQS on different facets are distinguished and named as shown in figure 1 (a). The whole NW SE and CL imaging (b) as well as the cross-sectional SE and CL imaging (c) revealed the variation of MQS luminescence in energy and positions. The Top MQS occasionally show emission. The Neck MQS do not show emission. The Shoulder, Chest, and Body MQS give intense but inhomogeneous emissions ranging from 2.8 – 3.2 eV. These origins are attributed to the variation of MQS structure depending on the facets as shown in the STEM image in (d). The variation of the MQS energies is originated in the MQS thickness and indium (In) concentration, while the inhomogeneity may be attributed to the roughness of MQS layers. The optimization of the emission from Body part is necessary to improve the performance of MQS-NW devices.