氮化硅层状陶瓷界面性能对力学性能的影响

通过加入Si₃N₄调节隔离层的性质, 研究了Si₃N₄/ BN 层状复合材料在不同界面结合情况下的力学性能变化规律。结果表明, 随着隔离层中Si₃N₄含量的提高, 基体片层之间的结合力不断增强。在结合力很强时, 层状材料具有与块状材料相同的破坏方式, 强度出现极值, 达到1000M Pa以上; 在结合力较弱时, 隔离层能够反复偏折裂纹, 层状材料表现出高达20M Pa?m1/2 的表观断裂韧性和约600M Pa 的强度。      

二元混杂粒径氮化硅填充硅橡胶的性能

在质量分数65%总氮化硅用量下,分别选取0.6 μm、3.0 μm、15 μm三种粒径氮化硅粒子,按照15 μm/0.6 μm=25、3.0 μm/0.6 μm=5两种组合所得混杂粒子来填充硅橡胶,研究两体系中的小粒子相对含量(Ws)变化对硅橡胶性能的影响.结果表明,硅橡胶热导率分别在Ws为20%及40%处达到最大值,...     

非平衡磁控溅射制备氮化硅薄膜及其性能研究

采用非平衡磁控溅射技术,通过改变氮气和氩气分压比P(N2)/P(Ar),在钛合金(Ti6Al4V)表面制备出不同结构及性能的氮化硅薄膜.结果显示,制备的氮化硅薄膜为非晶态结构,随着氮气分压的增加,Si-N键的含量增加,其对应的红外吸收峰逐渐变宽,并向高波数偏移.氮化硅薄膜的显微硬度、耐磨性随着P(N2)/P(Ar)的增加而先增加,当P(N2)/P(Ar)为0.25时,随着P(N2)/P(Ar)的增加,薄膜硬度及耐磨性稍有降低.氮化硅薄膜具有较好的膜/基结合力,当增大氮气和氩气分压比,薄膜的脆性随之增加.     

CF/PEEK复合材料界面层结构与性能关系研究

本文根据聚醚醚酮(PEEK)在碳纤维表面形式的横晶层的结构特征分析,建立了CF/FEEK复合材料界面层微观力学性能的理论方程,计算了界面层的杨氏模量.通过超声浸渍法测量复合材料的力学性能验证了计算结果,证明所进行的分析合理.计算结果表明,PEEK界面横晶层在垂直于纤维方向的杨氏模量E_r随PEEK结晶度的增大,或随横晶中PEEK晶片长度的增大而增大,并随晶片厚度的增大而减小.该界面层的上述模量值始终高于界面层附近球晶的模量值E_s,两者之间的比值E_T/E_s;依赖于横晶及球晶中的晶片长度b、厚度c和宽度a.由于界面层的模量高于非界面层的模量,当复合材料中纤维表面形成横晶时,复合材料将有较高的刚性.     

SrHfON高κ栅介质薄膜的漏电特性研究

采用射频反应磁控溅射法在p-Si(100)衬底上成功制备出SrHfON高k栅介质薄膜,并研究了Au/SrHfON/Si MOS电容的漏电流机制及应力感应漏电流(SILC)效应.结果表明,MOS电容的漏电流密度随N2流量的增加而减小.在正栅压下,漏电流主要由Schottky发射机制引起;在负栅压下,漏电流机制在低、中、高栅电场区时分别为Schottky发射、F-P发射和F-N隧穿机制.同时,Au/SrHfON/Si MOS电容表现出明显的SILC效应,经恒压应力后薄膜在正栅压下的漏电流由Schouky发射和F-P发射机制共同作用,且后者占主导地位.     

聚丙烯自组装复合的界面层分子相互作用研究

用分子自组装技术和ＦＴ－ＩＲ－ＡＴＲ光谱方法研究非熔融聚丙烯复合的界面层分子相互作用，结果表明，随着自级平壤 度的升高，ＰＰ非晶态的９７２吸收峰出现了峰加宽并移向低波数的现象，说明在界面层与ＥＶＡ的乙烯链段具有相互作用，而ＰＰ结晶态的９９７吸收变化不大。     

BST/BZT/BST多层薄膜结构与性能研究

利用脉冲激光沉积法在LaNiO3/LaAlO3(001)基片上生长了Ba0.6Sr0.4TiO3(BST)和Ba(Zr0.2Ti0.8)O3(BZT)单层薄膜,以及Ba(Zr0.2Ti0.8)O3/Ba0.6Sr0.4TiO3/Ba(Zr0.2Ti0.8)O3(BZT/BST/BZT)多层薄膜.X射线衍射(XRD)分析发现,BST、BZT和LNO薄膜都具有高度的(00l)取向.原子力显微镜(AFM)显示三种样品表面光滑无裂纹,晶粒尺寸和表面粗糙度相当.电容测试表明,相对BST、BZT单层薄膜,多层薄膜具有最大的品质因数42.07.表明多层薄膜在微波应用中具有很大的潜力.     

稀土烧结助剂对低介电多孔氮化硅陶瓷的性能影响

以CeO2,Y2O3和Yb2O3为烧结助剂,通过造粒、冷等静压成型和气氛压力烧结成功制备出介电常数ε低于3.0的氮化硅透波材料.伴随稀士氧化物烧结助剂量提高,材料介电性能不断下降,在7％时略有回升.含CeO2试样强度低于30MPa,而有Yb2O3的试样强度最高.通过XRD检测和SEM观察,发现其β相转化程度最高、长径比最大.     

蓝宝石和硅衬底上氮化硅薄膜的制备和性能研究

采用射频磁控反应溅射法,以高纯Si为靶材,高纯N2气为反应气体,在蓝宝石和硅衬底上制备了氮化硅薄膜.并对Si3N4薄膜的沉积速率、成分、结构及红外光学性能等进行了研究.实验结果表明,沉积薄膜中Si和N的比接近3∶4,形成了Si3N4化合物,呈非晶态结构.制备的Si3N4薄膜的硬度明显高于蓝宝石衬底的硬度,且与蓝宝石衬底结合牢固,可提供良好的保护性能.     

PECVD法沉积大尺寸氮化硅薄膜性能的研究

采用等离子体增强型化学气相沉积(PECVD)法在大尺寸玻璃基板上沉积氮化硅薄膜,对薄膜性能进行了研究,并从微观角度对所得结论进行了进一步分析与讨论。PECVD法在连续沉积氮化硅薄膜时,薄膜的厚度、沉积速率、均一性以及致密度会随镀膜基板数变化。结果表明,随镀膜基板数量的逐渐增加,氮化硅薄膜平均厚度呈上升趋势,均一性变好,薄膜致密度呈下降趋势。     

Influence of Interfacial LSMO Nanoparticles/Layer on the Vortex Pinning Properties of YBCO Thin Film

YBa₂Cu₃O_7?δ (YBCO) thin films have been deposited on bare and La_0.67Sr_0.33MnO₃ (LSMO) modified single crystal SrTiO₃ (STO) substrates. The effect of randomly distributed ferromagnetic LSMO nanoparticles and a complete LSMO layer, present at STO/YBCO interface, on the superconducting properties of YBCO thin films has been investigated by temperature dependent magnetization studies. The YBCO thin film on LSMO nanoparticles decorated STO substrate shows significant improvement in the critical current density and pinning force density as compared to the YBCO thin film deposited on bare STO substrate and this improvement is more significant at higher applied magnetic field. However, the LSMO/YBCO bilayer showed the improved flux pinning properties only up to a magnetic field of 1.5 T above which it deteriorates. In the case of LSMO/YBCO bilayer, the underlying LSMO layer gives rise to magnetic inhomogeneities due to domain structure, which leads to improved flux pinning properties limited to lower field. However, in the case of LSMO nanoparticles decorated substrate, the presence of LSMO nanoparticles at YBCO/STO interface seems to introduce magnetic inhomogeneities as well as structural defects, which might be acting as correlated pinning sites leading to improved flux pinning properties of the YBCO thin film over a wide range of applied magnetic field.     

半导体纳米晶体在薄膜晶体管中的应用

以非晶硅薄膜为核心的薄膜晶体管技术目前已经相当成熟,在该技术投入使用并且得以很好地优化之后,要想进一步提高薄膜晶体管的性能,就有必要开发新型的薄膜材料。近年来,由半导体纳米晶体构成的新型薄膜材料在晶体管中的应用越来越受到人们关注。利用半导体纳米晶体制备的薄膜晶体管有着较高的载流子迁移率和开关电流比,同时在其制备过程中可以在较低温度下大面积成膜,能够使用塑料等柔性衬底,因而具有明显的成本优势,发展前景广阔。着重介绍了几种颇具潜力的半导体(如硒化镉、碲化汞、硒化铅、锗、硅)纳米晶体在制备薄膜晶体管方面的应用。     

喷墨打印电极在薄膜晶体管中的应用

喷墨打印技术具有成本低、环境友好、效率高和直接写入等优势,被广泛应用于薄膜晶体管(TFTs)中图形化电极的制备。高密度、大尺寸、柔性和低能耗电子器件的快速发展,对打印电极质量提出了更高的要求。文章对导电墨水、喷墨打印技术及喷墨打印电极工艺优化进行了总结,并指出了现阶段喷墨打印电极在薄膜晶体管应用中存在的问题及今后的研究方向。     

Impact of Thin Film Thermophysical Properties on Thermal Management of Wide Bandgap Solid-State Transistors

Wide bandgap semiconductor solid-state transistors continue to have a wide array of applications that include power supplies, communications, electronic warfare, and multifunctional RF systems. Two viable wide bandgap semiconductor materials currently under investigation are silicon carbide (SiC) and gallium nitride (GaN). One interesting aspect of these devices is their ability to operate at elevated temperatures on the order of 500°C. At higher temperatures the heat capacity of semiconductors is constant, while the phonon mean free path is inversely proportional to the lattice temperature. This causes a significant reduction in the thermal conductivity over the operating temperature range. The submicron-scale conducting channels and junctions of wide bandgap devices can create highly localized heat fluxes on the order of several hundred kilowatts per square centimeter. Since these heat fluxes lead to localized hot spots within the electrically critical regions of the transistors, they can have a strong impact on device gain, power capability, and reliability. Quantifying the thermophysical properties of the underlying thin film materials is of critical importance for the accurate prediction of these localized temperature extremes.     

Organic Thin Film Transistors for Large Area Electronics

Organic thin‐film transistors (OTFTs) have lived to see great improvements in recent years. This review presents new insight into conduction mechanisms and performance characteristics, as well as opportunities for modeling properties of OTFTs. The shifted focus in research from novel chemical structures to fabrication technologies that optimize morphology and structural order is underscored by chapters on vacuum‐deposited and solution‐processed organic semiconducting films. Finally, progress in the growing field of the n‐type OTFTs is discussed in ample detail. The Figure, showing a pentacene film edge on SiO₂, illustrates the morphology issue.     

ZrO2薄膜的表层结构

用射频溅射技术制备了ＺｒＯ２薄膜，用恒正电子束分析该谱膜，发现它的的表层存在一高正电子吸收区，它与钇的表面富集有关，提出了相应的模型。