title: Investigating carrier localization and transfer in InGaN/GaN quantum wells with V-pits using near-field scanning optical microscopy and correlation analysis.
abstract: The V-pits and potential fluctuations in InGaN/GaN multiple quantum wells (MQWs) are key factors for understanding the performance of InGaN/GaN-based light-emitting diodes (LEDs). However, photoluminescence (PL) measurements using conventional optical microscopy only provide ensemble information due to the spatial resolution limit, known as the diffraction barrier, which hinders the analysis of dislocations and potential fluctuations. Here, in order to investigate the influence of the V-pits and potential fluctuations on local optical properties, we performed nanoscopic luminescence mapping for standard and V-pit InGaN/GaN MQWs samples with different sized V-pits using near-field scanning optical microscopy (NSOM) with illumination mode (I-mode) at various laser excitation powers. From the nanoscopic PL mapping data, we could clearly observe luminescence features associated with dislocations and potential fluctuations in the InGaN/GaN MQWs. We also employed correlation analysis to quantitatively analyze the nanoscopic PL mapping data for the different MQWs samples. Based on the results of NSOM PL with I-mode and correlation analysis, we could demonstrate that carrier transfer in the MQWs sample with large sized V-pits is suppressed by deeper potential fluctuations and higher energy barriers compared to the standard sample.
authors.affiliation: Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
authors.forename: MinKwan
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
authors.forename: Sunghan
authors.initials: S
authors.lastname: Choi
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
authors.forename: Joo-Hyung
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.|KI for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
authors.forename: ChungHyun
authors.initials: C
authors.lastname: Park
authors.affiliation: LED Research and Business Division, Korea Photonics Technology Institute, Gwangju 61007, Republic of Korea.
authors.forename: Tae-Hoon
authors.initials: TH
authors.lastname: Chung
authors.affiliation: LED Research and Business Division, Korea Photonics Technology Institute, Gwangju 61007, Republic of Korea.
authors.forename: Jong Hyeob
authors.initials: JH
authors.lastname: Baek
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.|KI for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
authors.forename: Yong-Hoon
authors.initials: YH
authors.lastname: Cho