63 lines
4.4 KiB
XML
63 lines
4.4 KiB
XML
// SiC 是很好的材料。
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// 其中，4H-SiC 是SiC的一种多型，它的性质更好，近年来随着外延工艺的成熟而获得了更多的关注。
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SiC is a promising wide-bandgap semiconductor material
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with high critical electric field strength and high thermal conductivity.
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It has been widely used in power electronic devices and has long attracted a lot of research
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@casady_status_1996 @okumura_present_2006.
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The 4H-SiC has a wider bandgap, higher critical electric field strength,
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higher thermal conductivity, and higher electron mobility along the c-axis than other polytypes.
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Currently, the 4H-SiC has gradually received more attention than other polytypes,
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thanks to the development of epitaxy technology and the increasing application in the new energy industry
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@tsuchida_recent_2018 @harada_suppression_2022 @sun_selection_2022.
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// TODO: 多引用一些近年来的文献，有很多
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// TODO: 这段是直接从上一篇论文中节选的，需要修改一下以避免重复。
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// 声子（量子化的原子振动）在理解晶体的原子结构以及热电性质方面起着重要作用。
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// 声子可以通过多种实验技术来探测，包括 EELS、IR 吸收谱等。
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// 拉曼光谱是最常用的方法，它提供了一种无损、非接触、快速和局部的声子测量方法，已被广泛用于确定晶体的原子结构（包括区分 SiC 的多型）。
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Phonons (quantized atomic vibrations) play a fundamental role
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in understanding the atomic structure as well as the thermal and electrical properties of semiconductors.
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They could be probed by various experimental techniques,
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such as electron energy loss spectroscopy and infrared absorption spectroscopy.
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// TODO: 这里加一两个 EELS 和 IR 的引用，有就行
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Among these techniques,
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Raman spectroscopy is the most commonly used method,
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// TODO: 增加一些引用，可以先不用收集文献给这里，最后把其它部分的全拿过来就行了。
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as it provides non-destructive, non-contact, rapid and spatially localized measurement of phonons
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that near the #sym.Gamma point in reciprocal space.
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Studies in Raman scattering of 4H-SiC have been conducted since as early as 1983
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// TODO: 找到那一篇
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and have been widely employed to identification of different SiC polytypes.
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// TODO: 找一些用来判定多型的文献
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// 近年来，更多信息被从拉曼光谱中挖掘出来。
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// LOPC 已经被用于快速估计 n 型 SiC 的掺杂浓度。
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// 层错的拉曼光谱也已经被研究，可以被用于检测特定结构层错的存在和位置。
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// 掺杂对拉曼光谱的潜在影响也已经被研究。
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// 然而，拉曼光谱上仍有一些不知来源的峰；同时，一些也缺少一些理论上预测应该存在的峰。
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// 此外，预测掺杂导致的新峰也没有说明原因。
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In recent years, increasingly rich information has been extracted from Raman spectra of 4H-SiC.
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Longitudinal optical phonon–plasmon coupling (LOPC) peek
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has been utilized to rapidly estimate the doping concentration in n-type SiC,
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// TODO: 增加使用 LOPC 估计 n 型掺杂浓度的论文
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and the existence of LO peek have been used to different the focus in p-type epilayer and in n-type substrate.
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// TODO: LOPC 来区分外延层和衬底的文献
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Peeks associated with some stacking faults have also been investigated
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and used to detect the presence and location of specific structural faults.
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// TODO: 缺陷峰，并补充对应的文献
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Moreover, the potential effects of doping on Raman spectra have been explored.
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// TODO: 掺杂导致的本征峰的变化的文献
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However, there are still some unsolved issues.
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Certain phonon modes predicted by theory remain unobserved,
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while there are still some unidentified peaks in the Raman spectra.
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An A1 peek was observed in some experiment but not in others, the reason for which is still unclear.
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In addition, relation between defects and Raman peek is still not very clear，
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potential raman peeks caused by defects and doping still need to be explored.
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// TODO: 调整语言，细化描述
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In this paper, we explored the phonon in 4H-SiC by three ways:
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symmetry analysis, first-principles calculations, and Raman experiment.
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We first investigated the phonon modes in perfect 4H-SiC,
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and then explored the phonon modes associated with defects and doping.
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// TODO: 描述自己做了什么，强调自己是第一次做到了什么。
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