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采用Ge浓缩法制备了高质量超薄绝缘体上锗硅(SiGe-on-insulator,SGOI)材料,然后在SGOI上通过超高真空化学气象沉积(UHVCVD)法外延了厚度为15 nm的超薄全局应变硅单晶薄膜,使用电子束光刻和反应离子刻蚀在样品上制备了一组纳米级尺寸不等的应变硅线条和应变硅岛,并利用TEM、SEM、Raman等分析手段表征样品.实验结果表明,本文制备的应变硅由于其直接衬底超薄SiGe层的低缺陷密度和应力牵制作用,纳米图形化的应变Si弛豫度远小于文献报道的无Ge应变硅或者具有Ge组分渐变层SiGe衬底的应变Si材料. 相似文献
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作为一种洁净能源,硅锗合金的热电转换性能的研究越来越受到人们的重视.本文重点研究了不同Ge浓度的硅锗合金以及Si、Ge单晶在300~1100K温度范围内,Seebeck系数随温度的变化.并对组分相同导电类型不同、晶向不同以及结晶状态不同的样品的Seebeck系数进行了比较.在研究温度区间,Seebeck系数的绝对值大小一般在200~600μV/K之间,随温度不同连续变化.通过对比发现SiGe合金的Seebeck系数大小不仅与Ge的浓度和温度有关,其他因素对其绝对值也有影响,其中晶向最为明显,表现出了明显的各向异性.此外,材料本身的电阻率除了作为一个热电参数影响最优值外,其大小还对Seebeck系数的绝对值有影响,即掺杂济浓度对Seebeck系数的影响. 相似文献
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采用射频等离子体增强化学气相沉积(RF-PECVD)技术,在200℃的衬底温度下,以SiH4和GeH4为反应气体,H2和He为稀释气体,制备微晶硅锗(μc-Si Gex∶H)薄膜.结合Raman,XRF,FTIR,AFM等测试,我们分析了不同流量He的掺入对高锗含量(Ge含量~40;)μc-Si1-x Gex∶H薄膜结构性能和光电特性的影响.结果表明,随着He稀释/H2稀释(CHe/H2=He/H2)的增加,薄膜的Ge含量基本保持不变,H含量减少,致密度提高,Ge悬挂键和微结构因子先减少后增大.CHe/H2=36;时,薄膜光电特性最好. 相似文献
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非晶锗的低温晶化和光学特性研究 总被引:1,自引:0,他引:1
本文采用直流磁控溅射在(100)硅衬底上沉积了单层锗薄膜,分别用拉曼光谱和X射线衍射研究了薄膜的结晶性,通过对结晶性的研究发现,在衬底温度为200℃时溅射功率为150W时结晶性开始变好,功率增至250W的过程,锗薄膜的择优取向发生(220)向(331)的变化.这样在无金属掺杂的情况下得到了结晶性较好的样品.光致发光结果表明,非晶锗在可见光区有较强的发光现象,发光峰位中心分别在648.1nm和713.0nm.发光峰位不随晶粒尺寸变化而变化,但峰强对晶粒大小的依赖性很强,平均晶粒较大的锗薄膜在可见光区发光现象不显著. 相似文献
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本文采用电子束蒸发法,室温下在Si(400)的基片上生长含锗(Ge)填埋层的非晶硅薄膜,其结构为a-Si/Ge/Sisubstrate,并在真空中进行后续退火.采用Raman散射(Raman Scattering)、X射线衍射(X-ray Diffraction)、高分辨电子扫描显微镜(HRSEM)、光学显微镜和热重差热分析(DSC)等手段,研究退火后样品晶化特性和晶化机理.结果表明,室温下生长的含有250 nm Ge填埋层的生长态样品在400℃退火5h,薄膜基本全部实现晶化,并表现出明显的Si (111)择优取向.样品分别在400℃、500℃、600℃和700℃退火后薄膜的横向光学波的波峰均在519cm-1附近,半高宽大约为6.1 cm-1,且均在Si(111)方向高度择优生长.退火温度为600℃的样品对应的晶粒尺寸约为20 μm.然而,在相同的薄膜结构(a-Si/Ge/Si substrate)的前提下,当把生长温度提高到300℃时,温度高达到700℃退火时间5h后,薄膜依然是非晶硅状态.差热分析表明,室温生长的样品,在后续退火过程中伴随界面应力的释放,从而诱导非晶硅薄膜重结晶成多晶硅薄膜. 相似文献
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We present an experimental investigation on the Ge doping level dependence of the Electron Paramagnetic Resonance (EPR) signal spectral features of the Ge(1), Ge(2) and E'Ge defects induced in Ge doped silica. We have studied samples produced by sol–gel or PCVD techniques and doped with different amounts of Ge up to 20% by weight. The samples were gamma or beta ray irradiated and successively they were thermally treated to isolate the EPR signals of the different point defects. The data show that the EPR line shapes of the Ge(1) and the Ge(2) centers are progressively modified for doping level higher than 1%, whereas the line shape of the E'Ge defect appears independent from the doping. Together with the EPR investigation, we have also recorded Raman spectra of the investigated samples. The Ge doping induces detectable modifications of Raman lines when the doping level is higher than 1% by weight. Basing on these observations, the structural modifications detected by Raman spectroscopy are tentatively considered the origin of the changes in the EPR features. 相似文献
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远程外延能够突破传统外延中晶格匹配、热匹配等限制,近年来得到了广泛的关注。Ⅲ-Ⅴ族和Ⅲ-氮化合物半导体已经成功在石墨烯上远程外延生长,但Ⅳ族半导体的远程外延很少被报道。本文首次借助于分子束外延技术在石墨烯上远程外延制备了半导体Ge纳米柱,研究了其生长特性及剥离转移。结果表明:远程外延生长的Ge纳米柱为[111]c晶向,集中分布在石墨烯的褶皱以及衬底Cu-Ni原子台阶处;随着生长温度的提高,Ge纳米柱的高度和密度逐渐下降,但直径差别不大,约为55~65 nm;此外,自组织生长的Ge纳米棒显示无应变的生长状态;引入少量Sn形成GeSn纳米柱,能够显著提升Ge纳米柱的面密度。同时,生长的Ge纳米柱可实现剥离,有望实现异质集成,应用于先进光电子器件等领域。 相似文献
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The density of vapor-deposited amorphous Ge films (a-Ge) was determined by spectrophotometry combined with Rutherford backscattering spectroscopy. It was found to be 0.99±3% of the bulk value for crystalline Ge (c-Ge). This density is in agreement with the Lorentz-Lorenz law which, based upon the existing infrared data on the index of refraction of a-Ge, suggests that the density of a-Ge should be close (within 4%) to that of c-Ge. 相似文献
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Measurements of optical absorption, dc conductivity and thermopower were carried out on glasses of the types (GeSe3.5)88sbPin12?xBix. The main results are: 1) observation of n-type conduction in the Ge20BixS80?x glasses containing high concentrations of Bi; 2) in the mixed doped glasses, transition from p-type for a Sb-doped glass (x = 0) to n-type on addition of Bi at nearly equal concentrations of Sb and Bi. The possible types of bonding of the Bi atoms in the structure and their influence on the electrical behaviour are examined. 相似文献
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The irreversible changes in conductivity occurring in evaporated amorphous Ge films just after deposition and during annealing are investigated in detail. Their analysis leads to a model for the structural relaxation of real amorphous networks. Electron diffraction and electron microscope experiments provide additional information on annealing effects and crystallization processes. 相似文献
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纳米Ge薄膜的制备及光致发光特性研究 总被引:1,自引:0,他引:1
采用直流磁控溅射技术在不同生长温度制备了一系列的Ge薄膜.应用拉曼散射、X射线衍射、光致发光等技术表征薄膜的结构.结果表明:Ge薄膜的结晶温度约为380℃,并且随着生长温度的升高,Ge的结晶性变好,晶粒长大;对不同尺寸Ge薄膜的光致发光研究表明:随着纳米Ge晶粒尺寸的减小,光致发光峰的相对强度逐渐增强,且发光峰位发生蓝移.用有效质量近似模型讨论了量子尺寸效应和介电限域效应对纳米Ge颗粒发光特性的影响. 相似文献
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《Journal of Non》2006,352(40-41):4346-4350
The present contribution presents X-ray absorption fine structure (XAFS) measurements and analysis of the Ge and Ga local structure in glass of Ca3Ga2Ge3O12 composition, doped with rare-earth metals (Ce, Eu, Ho, Er in the amount of 0.7 wt% and Nd in the amount of 1.0 wt%). The Ge and Ga ion neighborhoods in the considered glass samples have been compared with data obtained for undoped glass. The results have shown that introduction of rare-earth ions modifies the local structure around the Ga ions in the glass network, leaving the same occurrence ratio of the GaO4 and GaO6 structural units as in undoped Ca3Ga2Ge3O12 glass. At the same time, the GeO2 subsystem remains completely unaffected by the presence of rare-earth dopants. 相似文献
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