Open AccessTemperature dependence of Raman scattering in bulk 4H-SiC with different carrier concentration
Author(s) -
Hua Yang Sun,
Shao-Tzu Lien,
Zhi Ren Qiu,
Hong Chao Wang,
Ting Mei,
Liu C,
Zhe Chuan Feng
Publication year - 2013
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.21.026475
Subject(s) - raman spectroscopy , raman scattering , materials science , spectral line , doping , impurity , analytical chemistry (journal) , phonon , x ray raman scattering , optics , molecular physics , atomic physics , condensed matter physics , chemistry , physics , optoelectronics , organic chemistry , chromatography , astronomy
Raman spectra of three bulk 4H-SiC wafers with different free carrier concentration were measured at temperature from 80 K to 873 K. As temperature increases, Raman peaks of most optical phonon modes show monotonous down shift. An anomalous non-monotonous variation with temperature, was observed in the A(1) longitudinal optical (LO) mode from doped samples. Two methods of theoretical fitting, one-mode (LO-plasma coupled (LOPC) mode) and two-mode (A(1)(LO) + LOPC) fitting, are employed to analyze this anomalous phenomenon. Theoretical simulations for temperature dependent Raman spectra by using two methods are critically examined. It turns out that one-mode method conforms well the experimental results, while two-mode method is untenable in physics. The non-monotonous variation of blue-red shifts with temperature for LOPC mode from doped 4H-SiC could be explained by the influence from ionization process of impurities on the process of Raman scattering. A quantitative description on temperature dependent Raman spectra for doped 4H-SiC is achieved, which matches well to experimental data.