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微波等离子体化学气相沉积法在硅片上同时生长碳化硅和金刚石 被引量:1
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作者 唐春玖 符连社 +4 位作者 a.j.s.fernandes M.J.Soares Gil Cabral A.J.Neves J.Grácio 《新型炭材料》 SCIE EI CAS CSCD 北大核心 2008年第3期250-258,共9页
研究了衬底温度、核化密度、衬底表面预处理等工艺参数对微波等离子体化学气相沉积法在硅片上同时生长碳化硅和金刚石的影响。采用扫描电镜、X-射线衍射、喇曼光谱和红外光谱对样品进行了表征。结果表明:从高核化密度生长的金刚石膜中... 研究了衬底温度、核化密度、衬底表面预处理等工艺参数对微波等离子体化学气相沉积法在硅片上同时生长碳化硅和金刚石的影响。采用扫描电镜、X-射线衍射、喇曼光谱和红外光谱对样品进行了表征。结果表明:从高核化密度生长的金刚石膜中探测不到碳化硅;不论对硅衬底进行抛光预处理还是未抛光预处理,从低核化密度生长的金刚石厚膜中总能探测到碳化硅。碳化硅生长在硅衬底上未被金刚石覆盖的地方,或者是在金刚石晶核之间的空洞处。碳化硅形成和金刚石生长是同时发生的两个竞争过程。此研究结果为制备金刚石和碳化硅复合材料提供了一种新的方法。 展开更多
关键词 碳化硅 金刚石厚膜 红外光谱 微波等离子体气相化学沉积
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Structural effects induced by dialysis-based purification of carbon nanomaterials
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作者 A.D.Veloso A.M.Ferraria +5 位作者 A.M.Botelho do Rego A.S.Viana a.j.s.fernandes A.J.Fielding R.A.Videira M.C.Oliveira 《Nano Materials Science》 EI CAS CSCD 2024年第4期475-483,共9页
Dialysis plays a crucial role in the purification of nanomaterials but its impact on the structural properties of carbon nanomaterials was never investigated.Herein,a carbon-based nanomaterial generated electrochemica... Dialysis plays a crucial role in the purification of nanomaterials but its impact on the structural properties of carbon nanomaterials was never investigated.Herein,a carbon-based nanomaterial generated electrochemically in potassium phosphate buffer,was characterized before and after dialysis against pure water.It is shown that dialysis affects the size of the carbon domains,structural organization,surface functionalization,oxidation degree of carbon,and grade of amorphicity.Accordingly,dialysis drives the nanomaterial organization from discrete roundish carbon domains,with sizes ranging from 70 to 160 nm,towards linear stacking structures of small nanoparticles(<15 nm).In parallel,alcohol and ether(epoxide)surface groups evolve into more oxidized carbon groups(e.g.,ketone and ester groups).Investigation of the as-prepared nanomaterial by electron paramagnetic resonance(EPR)revealed a resonance signal consistent with carbon-oxygen centred radicals.Additionally,this study brings to light the selective affinity of the carbon nanomaterial under study to capture Na^(+)ions,a property greatly enhanced by the dialysis process,and its high ability to trap oxygen,particularly before dialysis.These findings open new perspectives for the application of carbon-based nanomaterials and raise awareness of the importance of structural changes that can occur during the purification of carbon-based nanomaterials. 展开更多
关键词 NANOCARBON Surface functionalization NMR XPS Hydrophilic carbon PARAMAGNETIC
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