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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.
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拉曼设备的型号是 LabRAM HR Evolution,使用背散射。
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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。
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有三个不同的入射配置,包括正入射、掠入射、边入射。
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考虑到 4 度斜切和 4H-SiC 几乎各向同性的折射率() @shaffer_refractive_1971 ,
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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。
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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。
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All our Raman experiments were performed using a LabRAM HR Evolution system with back-scattering configuration,
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where collected scattered light has a reversed wavevector direction compared to the incident light.
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A 532 nm laser was used in most experiments,
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while a 325 nm laser was used to observe Raman signals under ultraviolet excitation.
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Three different incidece configurations were used, as shown in @figure-incidence:
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normal incidence, where the laser beam is perpendicular to the epitaxial surface;
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Three different incidece configurations were used, as shown in @figure-incidence,
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including normal incidence, where the laser beam is perpendicular to the epitaxial surface;
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grazing incidence, where the laser beam is nearly parallel to the epitaxial surface;
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and edge incidence, where the laser beam is incident at the edge of the wafer, instead of the epitaxial surface.
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Taking the
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During the experiments, a 100 μm confocal pinhole was used to improve the z-direction resolution @song_depth_2020.
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and the refracted light propagates with about 25 #sym.degree to the c axis;
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Taking the 4° offcut angle
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and the nearly isotropic refractive index 2.73 of 4H-SiC @shaffer_refractive_1971 into account,
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the wavevector in 4H-SiC during grazing incidence is about 25° to the c axis.
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During normal incidence, a 100 μm confocal pinhole was used to improve the z-direction resolution @song_depth_2020;
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while during other configurations, 200 μm confocal pinhole was used to improve the signal-to-noise ratio.
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#include "figure-incidence.typ"
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== Simulation details
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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。
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无缺陷的声子在多大的模型中计算。
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带缺陷的情况下,模型大小,每个模型的代号和缺陷结构。
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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。
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声子计算使用 phonopy phono3py ufo,BEC 修正的算法。
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// 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。
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// 考虑到斜切,则大约是 24 度。
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