Micro-Raman investigation on the size effects of surface optical phonon modes in single cone-shape InGaN/GaN microrods

• Published in: Applied surface science 2020-05, Vol.512, p.145656, Article 145656
• Main Authors: Liao, Hui, Wen, Peijun, Yu, Guo, Akbar, Muhammad Saddique, Li, Junchao, Lang, Rui, Lei, Menglai, Mi, Zehan, Hu, Xiaodong
• Format: Article
• Language: English
• Subjects: GaN; Microrod; Raman; SO mode
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.145656

[Display omitted] •The SO mode of single cone-shape InGaN/GaN microrods was investigated by micro-Raman investigation.•The size of the microrod would lead to the SO mode.•The frequency of SO mode is changed with different radius of microrod. As one of the third generation semiconductor representative materials, nitride has been commonly used in the field of semiconductor optoelectronics. Low dimensional structures of GaN have become research hotspot. In this paper, the size effects of single InGaN/GaN core-shell microrods on the surface optical phonon mode (SO mode) are studied based on micro-Raman technology. The experimental results show that the size of the microrod would lead to the SO mode. Furthermore, the frequency of SO mode is changed with different radius of microrod. The larger the radius is, the higher the frequency of SO mode. Combined with theoretical calculation, it is found that the experimental results are in agreement with calculation. In addition, the experimental results show that the coupling of the free carrier and the longitudinal optical phonon caused the Raman shift of E1 (LO) mode. Based on this, we obtain the distribution of carrier concentration along the [0 0 0 1] growth direction.