Open AccessTemperature-dependent ultraviolet Raman scattering and anomalous Raman phenomenon of AlGaN/GaN heterostructure
Author(s) -
Yanli Liu,
Dunjun Chen,
Guangsheng Wei,
Zhonghai Lin,
Aiguo He,
Meihua Li,
Pingjian Wang,
Rong Zhang,
YuXiang Zheng
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.004781
Subject(s) - raman spectroscopy , phonon , materials science , raman scattering , heterojunction , condensed matter physics , ultraviolet , dispersion (optics) , optoelectronics , electric field , optics , physics , quantum mechanics
Temperature-dependent ultraviolet (UV) Raman scattering from AlGaN/GaN heterostructure is investigated. Compared to the visible Raman spectrum, four new peaks at 600, 700, 780, and 840 cm -1 are observed in the UV Raman spectrum. The peak at 780 cm -1 is from the AlGaN A 1 (LO) mode. According to the calculated dispersion relations of the interface phonon modes in the AlGaN/GaN heterostructure, the peaks at 600 and 840 cm -1 correspond to interface phonon modes. Meanwhile, the peak at 700 cm -1 is attributed to the disorder-active mode near the 2DEG interface. Due to the near-resonant enhancement effect, the intensities of the GaN A 1 (LO) mode, interface phonon modes, disorder active mode and the AlGaN A 1 (LO) mode exhibit different temperature dependence. Furthermore, the frequencies of the interface phonon modes and the disorder active mode show anomalous temperature dependence, which can be attributed to the strong built-in electric field near the 2DEG interface.