Surface-Induced Carrier Localization and Recombination Characteristics in InGaN/GaN Quantum Dots in Nanopillars

• Published in: Journal of physical chemistry. C Vol. 123; no. 9; pp. 5699 - 5704
• Main Authors: Wang, Z. L, Hao, Z. B, Yu, J. D, Wang, L, Wang, J, Sun, C. Z, Xiong, B, Han, Y. J, Li, H. T, Luo, Y
• Format: Journal Article
• Language: English
• Published: American Chemical Society 07.03.2019
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.8b11830

In quantum structures and nanomaterials, surface conditions have significant influence on the material’s optical and electrical properties; hence, surface modification is an inevitable and critical step during the fabrication process of optoelectronic devices. A comprehensive understanding on how surface conditions impact on the performance is a key issue; however, it is difficult to apply experimental techniques to study the surface physics in the atomic scale. In this paper, the photoluminescence properties of InGaN/GaN quantum dots in nanopillar samples were carefully investigated and compared after applying various surface manipulation techniques. Spectroscopic results show that the localization features including recombination energy level and peak shift with temperature are extremely sensitive to surface treatment. Based on the localized state ensemble model, a quantitative analysis is performed taking into account of thermal activation and density of states distribution function of localization. The correlation between optical properties and the physical mechanism of surface modification is established. This spectroscopic technique along with the analytical method provides physical insights and reliable basis for nanoscale device evaluation and optimization.