Effects of lanthanum ion-implantation on microstructure of oxide film formed on Co-Cr alloy

Isothermal and cyclic oxidizing behavior of Co-40Cr alloy and its lanthanum ion-implanted samples were studied at 1000 ℃ in the air by thermal-gravimetric analysis （TGA）. Scanning electronic microscopy （SEM） and transmission electronic microscopy （TEM） were used to examine the morphology and structure of oxide film after oxidation. Secondary ion mass spectrum （SIMS） method was used to examine the binding energy change of chromium caused by La-doping and its influence on the formation of Cr2O3 film. laser Raman spectrum was used to examine the stress changes within the oxide film. It was found that lanthanum implantation remarkably reduced isothermal oxidizing rate of Co-40Cr and improved anti-cracking and anti-spalling properties of Cr2O3 oxide film. The reasons for the improvement were mainly that the implanted lanthanum reduced the grain size and internal stress of Cr2O3 oxide and increased high temperature plasticity of the oxide film. Lanthanum mainly existed on the outer surface of Cr2O3 oxide film in the form of fine La2O3 and LaCrO3 spinel particles.     

金掺杂HgCdTe气相外延生长及二次离子质谱研究

通过气相外延技术生长了Au掺杂的Hg1-xCdxTe薄膜材料。利用傅里叶光谱仪和金相显微镜对外延材料进行了表征。通过二次离子质谱(Secondary Ion Mass Spectroscopy, SIMS)技术分析了Au在Hg1-xCdxTe外延层以及CdZnTe衬底中的纵向分布趋势。利用SIMS技术还分析了I、II族和VI、VII族杂质在Hg1-xCdxTe外延层以及CdZnTe衬底中的纵向分布趋势,发现衬底和外延层的过渡区具有吸杂作用。研究结果对提高探测器的性能具有指导意义。     

Surface engineering in Cu(In,Ga)Se2 solar cells

Surface modifications of three‐stage co‐evaporated Cu(In,Ga)Se₂ (CIGS) thin films are investigated by finishing the evaporation with gallium‐free (CuInSe₂, CIS) stages of various lengths. Secondary‐ion mass spectrometry shows substantial interdiffusion of indium and gallium, smearing out the Ga/(Ga + In) profile so that the addition of a CIS layer merely lowers the gallium content at the surface. For the thinnest top layer, equivalent to 20 nm of pure CIS, X‐ray photoelectron spectroscopy does not detect any compositional difference compared with the reference device. The modifications are evaluated electrically both by temperature‐dependent characterisation of actual solar‐cell devices and by modelling, using the latest version of scaps‐1d (Electronics and Information Systems, Ghent University, Belgium). The best solar‐cell device from this series is obtained for the 20 nm top layer, with an efficiency of 16.6% after antireflective coating. However, we observe a trend of decreasing open‐circuit voltage for increasingly thick top layers, and we do not find direct evidence that the lowering of the gallium concentration at the CIGS surface should generally be expected to improve the device performance. A simulated device with reduced bulk and interface defect levels achieves nearly 20% efficiency, but the trends concerning the CIS top layer remain the same. Copyright © 2011 John Wiley & Sons, Ltd.     

Development of gallium gradients in three‐stage Cu(In,Ga)Se2 co‐evaporation processes

We use secondary‐ion mass spectrometry, X‐ray diffraction and scanning electron microscopy to investigate the development over time of compositional gradients in Cu(In,Ga)Se₂ thin films grown in three‐stage co‐evaporation processes and suggest a comprehensive model for the formation of the well‐known ‘notch’ structure. The model takes into account the need for compensating Cu diffusion by movement of group‐III ions in order to remain on the quasi‐binary tie line and indicates that the mobilities of In and Ga ions differ. Cu diffuses towards the back in the second stage and towards the front in the third, and this is the driving force for the movement of In and Ga. The [Ga]/[In + Ga] ratio then increases in the direction of the respective Cu movement because In has a higher mobility at process conditions than has Ga. Interdiffusion of In and Ga can be considerable in the (In,Ga)₂Se₃ film of the first stage, but seems largely to cease in Cu(In,Ga)Se₂ and shows no signs of being boosted by the presence of a Cu₂Se layer. Copyright © 2011 John Wiley & Sons, Ltd.     

PVT法掺钒SiC单晶生长电阻率变化规律研究

在采用COREMA方法测试SiC晶片电阻率时发现同一晶片电阻率相差较大,主要体现在高阻(>105Ω.cm量级)和低阻(<105量级)并存,有的甚至超高阻(>1012量级)和低阻并存,针对这一测试结果,开展了相关的实验研究,SiC单晶半绝缘性能的实现是通过在单晶生长过程中掺入深能级杂质V来补偿浅施主N和浅受主B,利用二次质谱(SIMS)对同一晶片不同区域的杂质元素V、N和B含量进行测试,结果发现晶片中V和N的含量都在1×1017量级时会出现同一晶片不同区域电阻率相差较大的情况,而当V含量在1×1017量级,N含量在5×1016量级以下时,可制备电阻率均匀性好的半绝缘SiC单晶。     

Multitechnique study of hexatriacontane surfaces modified by argon and oxygen RF plasmas: effect of treatment time and functionalization,and comparison with HDPE

Hexatriacontane (C₃₆H₇₄) has been used as a model molecule for the study of the surface modifications of high-density polyethylene (HDPE) in argon and oxygen radio-frequency (RF) plasmas. The combination of static secondary ion mass spectrometry (SIMS), ion scattering spectroscopy (ISS), X-ray photoelectron spectroscopy (XPS), and contact angle measurements has constituted a powerful method for the investigation of the surface modifications induced by the plasma treatments. The surface degradation and functionalization are shown to depend on both the nature of the treated material and the nature of the plasma atmosphere. The SSIMS results obtained on plasma-modified hexatriacontane and HDPE are compared in order to identify the nature of the functionalities present at the plasma-treated surfaces. Finally, plasma treatment ¹⁸O atmosphere was performed on HDPE, C₃₆H₇₄, and polystyrene (PS). In that case, the isotopic specificity of both ISS and SIMS allowed the determination of the relative concentrations of ¹⁶O and ¹⁸O in relation to the probed depth and plasma atmosphere.     

Influence of surface treatment on the durability of stainless steel sheets bonded with epoxy

Fifteen different surface treatments were used to bond AISI 304 stainless steel. The objectives of the programme were to select treatments able to produce durable adhesive bonds and to contribute to the understanding of interface bonding phenomena and of phenomena responsible for debonding while ageing. Peel and sheer tests were carried out to assess the behaviour of the bonded joints at the initial state and after ageing. The test results indicate that only two treatments, sulphuric chromic acid anodization and nitric acid anodization, exhibit a high performance level after exposure to a moist environment. The chemical and physical properties of surfaces were determined. The surface morphology was observed with a scanning electron microscope, and chemical composition was studied by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. A correlation between bond durability, surface morphology, and oxide film composition was established.     

LiOH水溶液提高Zr-4合金腐蚀速率的机理

在不同水化学条件下的高压釜中研究了Zr-4合金在LiOH水溶液中的耐腐蚀性能.结果表明,不同的腐蚀介质对氧化膜内的压应力和t-ZrO2的含量的影响有很大不同;Zr-4合金在LiOH或KOH水溶液中腐蚀时,Li 比K 进入氧化膜深而且浓度高;在LiOH水溶液中腐蚀时,氧化膜中OH-的浓度比在KOH水溶液中高.锆合金在LiOH水溶液中腐蚀时,氧化膜的生长主要是通过OH-从合金的表面向内扩散,与锆反应生成氧化锆和原子氢.Li 半径较小,容易进入氧化膜,因此较多的OH-进入氧化膜的深处,并与t-ZrO2中的氧空位反应,使t-ZrO2向m-ZrO2转变.这导致氧化膜出现裂纹,使氧化膜中的压应力松弛,降低氧化膜的保护能力,提高了锆合金的腐蚀速率.     

InGaAlP外延片的微分析

介绍了电子显微镜和二次离子质谱仪(SIMS)两种当前主要的微分析工具在四元InGaAlP发光二极管(LED)外延片分析过程中的应用,讨论了它们各自的适用领域,指出两者有机的结合可以得到比较全面的分析结果,为工艺监控和工艺改进提供了参考.     

硅中磷杂质的SIMS定量检测

利用SIMS(二次离子质谱仪)测试了国产重掺砷硅单晶中的痕量杂质磷,通过样品前期处理和精密的仪器调试,使检测时间缩短,并使硅中磷的检测限达到5×10¹³ cm^-3。实验结果表明,样品的前期处理工艺会对检测结果产生影响。不同处理工艺得到的样品,在表面粗糙度方面产生区别。不同的表面粗糙度,影响到样品的测试时间和测试精度。同时,通过仪器调试,仪器的真空度达到1×10^-10 torr,使测试背底和检测限降低。