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@@ -22,30 +22,29 @@ The Si/C ratios of the five wafers during growth were 0.7, 1.2, 1.6, 2.4, and 2.
拉曼设备的型号是 LabRAM HR Evolution使用背散射。
大部分实验中,我们使用 532 nm 的激光,少部分实验中使用 325 nm 的激光以观测紫外拉曼。
有三个不同的入射配置,包括正入射、掠入射、边入射。
考虑到 4 度斜切和 4H-SiC 几乎各向同性的折射率() @shaffer_refractive_1971
考虑到 4 度斜切和 4H-SiC 几乎各向同性的折射率(2.73 @shaffer_refractive_1971 掠入射的入射角大约为 25 度。
在正散射过程中,我们使用 100 微米的共焦针孔,以尽可能提高 z 方向的分辨率 @song_depth_2020
All our Raman experiments were performed using a LabRAM HR Evolution system with back-scattering configuration,
where collected scattered light has a reversed wavevector direction compared to the incident light.
A 532 nm laser was used in most experiments,
while a 325 nm laser was used to observe Raman signals under ultraviolet excitation.
Three different incidece configurations were used, as shown in @figure-incidence:
normal incidence, where the laser beam is perpendicular to the epitaxial surface;
Three different incidece configurations were used, as shown in @figure-incidence,
including normal incidence, where the laser beam is perpendicular to the epitaxial surface;
grazing incidence, where the laser beam is nearly parallel to the epitaxial surface;
and edge incidence, where the laser beam is incident at the edge of the wafer, instead of the epitaxial surface.
Taking the
During the experiments, a 100 μm confocal pinhole was used to improve the z-direction resolution @song_depth_2020.
and the refracted light propagates with about 25 #sym.degree to the c axis;
Taking the offcut angle
and the nearly isotropic refractive index 2.73 of 4H-SiC @shaffer_refractive_1971 into account,
the wavevector in 4H-SiC during grazing incidence is about 25° to the c axis.
During normal incidence, a 100 μm confocal pinhole was used to improve the z-direction resolution @song_depth_2020;
while during other configurations, 200 μm confocal pinhole was used to improve the signal-to-noise ratio.
#include "figure-incidence.typ"
== Simulation details
无缺陷的模型大小。带缺陷的情况下,模型大小,每个模型的代号和缺陷结构
无缺陷的声子在多大的模型中计算
带缺陷的情况下,模型大小,每个模型的代号和缺陷结构。
第一性原理计算使用 VASP使用 PBE PAW平面波截断能K 点网格,涂抹,自洽和弛豫的 threshold。
声子计算使用 phonopy phono3py ufoBEC 修正的算法。
// 在略入射的过程中,角度的关系不大(即使是 60 度入射,和 90 度入射差别也不大)。因此我们按照折射角 20 度的结果计算。
// 考虑到斜切,则大约是 24 度。