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MoO_2氢还原机理探索 被引量:5
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作者 武洲 冯鹏发 +2 位作者 李晶 厉学武 卜春阳 《中国钼业》 2011年第5期42-45,共4页
在MoO2还原为钼粉的过程中,大颗粒钼粉(指筛上物)的杂质含量会远远高于小颗粒钼粉。本文采用"核收缩"的理论模型来解释了这一现象。在MoO2氢还原为Mo的过程中,产生一种比起钼的其他化合物挥发性更强的氧化钼的水合物MoO3.H2O... 在MoO2还原为钼粉的过程中,大颗粒钼粉(指筛上物)的杂质含量会远远高于小颗粒钼粉。本文采用"核收缩"的理论模型来解释了这一现象。在MoO2氢还原为Mo的过程中,产生一种比起钼的其他化合物挥发性更强的氧化钼的水合物MoO3.H2O或MoO2(OH)2,这种水合物结合从MoO2收缩核中扩散出来的杂质,挥发沉积到长大的Mo颗粒的表面。大颗粒Mo粉的表面积大、表面能低,挥发性水合物更容易沉积在由众多细小颗粒团聚而成的大颗粒表面,从而造成大颗粒钼粉的杂质含量较高。 展开更多
关键词 钼粉 二氧化钼 氢还原 团聚 化学气相迁移
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氧化还原法制备钨晶须及其生长机理研究
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作者 马运柱 石玉斌 +1 位作者 刘文胜 李静 《材料科学与工艺》 EI CAS CSCD 北大核心 2012年第3期117-120,126,共5页
研究了钨晶须的制备工艺,并分析了其生长机理.采用X射线衍射、扫描电镜、能谱分析、透射电镜对制备的钨晶须进行物相、形貌、成分、微观结构的分析和表征.研究表明:钨晶须长度大致在1~10μm,直径在1μm以下,部分达到纳米级;晶须为单晶... 研究了钨晶须的制备工艺,并分析了其生长机理.采用X射线衍射、扫描电镜、能谱分析、透射电镜对制备的钨晶须进行物相、形貌、成分、微观结构的分析和表征.研究表明:钨晶须长度大致在1~10μm,直径在1μm以下,部分达到纳米级;晶须为单晶bcc结构,生长方向为<110>;钨晶须形成过程为钨粉及其氧化产物与水汽反应生成气相水合物WO2(OH)2,遇氢气还原后形核并沉积,进而定向生长为晶须结构,钨晶须的生成遵循VS机理. 展开更多
关键词 钨晶须 氧化还原 化学气相迁移 VS机理
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Carrier Transport Properties in the Doped Micro - crystalline Silicon Films
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作者 ZHONG Bo-qiang (Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 ,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第3期186-189,共4页
Doped micro-crystalline silicon films are deposited at temperatures as low as 400 ℃ by the catalytic chemical vapor deposition method using a silane and hydrogen gas mixture. Electrical properties such as the carrier... Doped micro-crystalline silicon films are deposited at temperatures as low as 400 ℃ by the catalytic chemical vapor deposition method using a silane and hydrogen gas mixture. Electrical properties such as the carrier concentration and the Hall mobility are investigated for various measuring temperatures. It is found that the grains of micro-crystalline silicon are preferentially oriented along the (220) direction , and that the Hall mobility is larger than 8 cm 2·V -1 ·s -1 , the carrier concentration is about 1×10 17 cm -1 ~1×10 19 cm -3 at room temperature. 展开更多
关键词 Catalytic Chemical Vapor Deposition Hall Mobility Micro-crystalline Silicon CLC number:TN201 O431 Document code:A
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High-quality bilayer graphene grown on softened copper foils by atmospheric pressure chemical vapor deposition
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作者 Qiao Chen Qiyang Song +6 位作者 Xin Yi Qiao Chen Wenjia Wu Meirong Huang Chuanwen Zhao Shun Wang Hongwei Zhu 《Science China Materials》 SCIE EI CSCD 2020年第10期1973-1982,共10页
Bilayer graphene(BLG)shows great application prospect and potential in next-generation electronics because of its unique electrical and mechanical properties.However,the scalable synthesis of large-area high-quality B... Bilayer graphene(BLG)shows great application prospect and potential in next-generation electronics because of its unique electrical and mechanical properties.However,the scalable synthesis of large-area high-quality BLG films is still a great challenge,despite the maturity of chemical vapor deposition(CVD)technique.In this study,we report a robust method to grow BLGs on flat,softened Cu foils by atmospheric pressure CVD.A moderate amount of residual oxygen accelerates the growth of BLG domains while suppressing the formation of multilayers.Raising the nucleation density at low hydrogen pressure efficiently increases the film continuity.Based on the optimized CVD process,the growth of graphene films on 4×4 cm^2 Cu foils with an average BLG coverage of 76%is achieved.The morphology and structure characterizations demonstrate a high quality of the BLG.Dual gate field-effect transistors are investigated based on AB-stacked BLG,with a tunable bandgap and high carrier mobility of up to 6790 cm2 V^−1 s^−1 at room temperature. 展开更多
关键词 GRAPHENE BILAYER chemical vapor deposition Cu foil
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