首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
单根In掺杂的n-ZnO纳米线/p+-Si异质结的紫外电致发光   总被引:1,自引:0,他引:1  
采用化学气相沉积的方法在In0.1Ga0.9N衬底上生长出In掺杂的n-ZnO纳米线阵列。电学输运测量得到单根n-ZnO纳米线的电阻率为0.001 Ω cm,比同样方法在GaN衬底上生长的ZnO纳米线低约20倍。这个结果表明来自于In0.1Ga0.9N衬底中的In原子在高温生长过程中可能被掺入ZnO纳米线。制备成功单根n-ZnO纳米线/p+-Si异质结构并研究了其电致发光特性。室温下电致发光光谱中可以看到一个窄的ZnO激子峰(约380 nm)和一个中心位于700 nm 的来自Si衬底表面自然氧化硅发光中心的发光峰。  相似文献   

2.
通过在N2气氛中将金属镓加热到900℃,在镓颗粒表面大面积生长出-βGa2O3纳米线.采用激光拉曼光谱仪、扫描电子显微镜和透射电子显微镜对产物的结构和形貌进行了表征.结果表明,所得产物为单斜相单晶结构Ga2O3纳米线,其直径为50-100 nm,长度为30-100μm.提出了Ga2O3纳米线可能的生长机理.室温下研究了所得Ga2O3纳米线的光致发光特性,观察到起源于氧空位的电子与镓-氧空位对上的空穴复合产生的发光峰在457 nm的蓝光发光.  相似文献   

3.
GaN纳米线的成核及生长机制研究   总被引:3,自引:0,他引:3  
报道了利用CVD方法研究GaN纳米线的成核和生长机理的最新结果,着重强调了生长温度和催化剂对纳米线生长的影响。通过分析GaN纳 米线的形貌、显微结构与生长温度、催化剂等影响因素之间的依赖关系,详细研究了GaN纳米线的生长过程。这一结果有助于了解一维纳米结构的生长机理,实现纳米材料的可控制生长,并有可能直接应用于GaN纳米器件的制备。  相似文献   

4.
以乙酰丙酮合铟[In(acac)3](acac=acetylacetonate)作为单源前驱体,Au为催化剂,采用化学气相沉积法,于较低温度(550℃)下成功制得了In2O3纳米线.用X射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和能量分散光谱(EDS)对In2O3纳米线进行了表征;制得的In2O3纳米线具有单晶结构,平均直径约为80nm,长度达十几微米,其生长服从气一液一固机理.光致发光研究发现,In2O3纳米线在483nm处有一个强的发射峰,这可归因于氧空位的存在.  相似文献   

5.
以硅烷为反应气体,温度为850~1100℃,在(100)取向的单晶硅片上,采用化学气相沉积法生长了一维硅纳米线.用扫描电子显微镜观察了硅纳米线的表面形貌,用X射线衍射仪研究了硅纳米线生长结构与反应温度的关系.分析了不同实验条件对硅纳米线生长结构的影响,并对一维硅纳米线与块体硅的光致发光(PL)特性进行了分析比较.  相似文献   

6.
氧对纳米ZnO薄膜晶体结构和光致发光的影响   总被引:1,自引:1,他引:1  
ZnO是一种直接带半导体材料,在光电领域中和GaN一样受到关注.ZnO不仅有与GaN相似的晶体结构,而且它的激子结合能高达60meV,是GaN的2.4倍.采用射频(RF)磁控溅射法在n-Si(001)衬底上生长ZnO薄膜,XRD谱测量显示出氧压对ZnO薄膜的晶体结构有显著影响,用波长为325nm的激光激发,观察到在445nm处有一强的光致发光峰,它来自于氧空位浅施主能级上的电子跃迁到价带,分析了发光峰与氧压的关系以及退火对它的影响。  相似文献   

7.
采用脉冲激光沉积技术,在Al2O3(0001)衬底上生长GaN薄膜,利用X射线衍射(XRD)、原子力显微镜(AFM)研究了不同沉积温度,不同沉积压强对所生长的GaN薄膜晶体结构特征的影响.研究表明,沉积温度影响GaN薄膜结构,在700~750℃沉积范围内随温度升高,所沉积生长的GaN薄膜具有良好的结晶质量.在5~10Pa沉积气压范围内,提高气压有利提高GaN薄膜的结晶质量.  相似文献   

8.
用基于密度泛函理论平面波超软赝势法对六方GaN空位型本征点缺陷进行了理论研究.计算了GaN、Ga0.875N,Ga0.750N,GaN0.875和GaN0.750等5种模型(Ga和N不同比例情况下的空位型GaN)的能带结构、差分电子密度、电子态密度,详细讨论了各种空位缺陷对GaN性能的影响.结果显示,带隙宽度随着Ga空位或N空位的增加而不断增大,Ga空位是一种受主缺陷,N空位是施主缺陷;N空位的增加导致GaN电导率的下降.  相似文献   

9.
ZnO纳米线和纳米杆的热氧化前驱体法制备及拉曼分析   总被引:1,自引:0,他引:1  
采用热氧化线状Zn前驱体法,在压强为5 Pa,温度分别为400 ℃和600 ℃的条件下,制备了单晶ZnO纳米线和纳米杆.用SEM观察了样品的表面形貌,用XRD和HRTEM研究了样品的晶体结构和形态,分析表明细ZnO纳米线是通过"自催化液-固"过程沿着[21-1-10]方向生长,而ZnO纳米杆则依照气-固机制沿着[0001]方向生长.在室温下测量了514.5 nm激发下的拉曼光谱,结果表明由细ZnO纳米线和粗轴组成的样品拥有较多的氧空位,而在高温下氧化得到的ZnO纳米杆的结晶程度比较好,晶格结构更加完整.  相似文献   

10.
氧化锌纳米线阵列的无模板法制备   总被引:1,自引:0,他引:1  
报道了一种氧化锌纳米线阵列的无模板电沉积制备方法.这种方法制备的氧化锌纳米线阵列具有(0001)趋向.单根氧化锌纳米线具有很好单晶结构,因而氧化锌阵列具有优异的紫外发光特性.其生长过程可以概括为衬底诱导的趋向氧化锌晶核在平衡状态下的快速生长.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号