SmCo(Al,Si)/Cr硬磁薄膜的结构与性能

在优化后的磁控溅射和退火条件下 ,制备SmCo(Al,Si) /Cr硬盘磁记录介质及硬磁薄膜 .实验结果表明 ,Sm摩尔分数为 31.6 % ,Cr缓冲层为 6 6nm ,Sm(Co ,Al,Si) 5磁性层为 30nm时 ,制得的Sm(Co ,Al,Si) 5/Cr薄膜的矫顽力Hc 为 187.8kA/m ,剩磁比S =Mr/Ms≈ 0 .94;在 5 0 0℃保温 2 5min退火后 ,矫顽力Hc 达10 42 .5kA/m ,剩磁比S≈ 0 .92 ,从而制成了较理想的硬磁薄膜     

Al掺杂对ZnO薄膜晶体结构的影响

采用溶胶-凝胶工艺在Si(111)衬底上制备了ZnO薄膜,利用X射线衍射仪对薄膜的晶体结构进行了分析讨论.结果表明,当掺杂量Al3 浓度增大时,晶体产生的张应力使晶格常数变大,衍射峰向小角度方向移动;相反,当Al3 浓度减小时,压应力使衍射峰向大角度方向移动.     

Structural and magnetic properties of ZnFe2O4 films deposited by low sputtering power

To validate the correctness of the Hartman-Perdok Theory (HPT), which indicates that the {111} planes have the lowest surface energy in spinel ferrites, the {111} plane orientated ZnFe₂O₄ thin films on Si(100), Si(111), and SiO₂(500 nm)/Si(111) substrates were obtained through a radio frequency (RF) magnetron sputtering method with a low sputtering power of 80 W. All of the experiments prove that the atom energy determined by sputtering power plays an important role in the orientated growth of the ZnFe₂O₄ thin films, and it matches well with HPT. The ZnFe₂O₄ thin films exhibit ferromagnetism with a magnetization of 84.25 kJ/mol at room temperature, which is different from the bulk counterpart (antiferromagnetic as usual). The ZnFe₂O₄ thin films can be used as high-quality oriented inducing buffer layers for other spinel (Ni, Mn)Zn ferrite thin films and may have high potential in magnetic thin films-based devices.     

Sb掺杂ZnO薄膜的缺陷和光学性质研究

采用磁控溅射方法在6H-SiC单晶片上制备了锑(Sb)掺杂的氧化锌(ZnO)薄膜.利用X射线衍射(XRD)和X射线光电子能谱(XPS)对样品的结晶质量和成分进行了测试.结果表明所得到的ZnO∶Sb薄膜结晶质量良好,掺Sb浓度为原子数分数1%,并且掺入的Sb原子处于Zn原子的位置.利用低温及变温光致发光谱(PL)研究了ZnO∶Sb薄膜的光学性质,观察到了与Sb有关的A0X发射,并且计算得到其受主能级为150meV.分析认为掺Sb的ZnO薄膜中受主来源于SbZn-2VZn复合缺陷.     

Preparation of Cu（In,Ga）Se2 thin film by sputtering from Cu（In,Ga）Se2 quaternary target

Cu(In,Ga)Se2 (CIGS) thin films were prepared by directly sputtering Cu(In,Ga)Se2 quaternary target consisting of Cu:In:Ga:Se 25:17.5:7.5:50 at%. The composition and structure of CIGS layers have been investigated after annealing at 550 ℃ under vacuum and a Se-containing atmosphere. The results show that recrystallization of the CIGS thin film occurs and a chalcopyrite structure with a preferred orientation in the (112) direction was obtained. The CIGS thin film annealed under vacuum exhibits a loss of a portion of Se, while the film annealed under Se-containing atmosphere reveals compensation of Se. Several solar cells with three different absorber thicknesses were fabricated using a soda lime glass/Mo/CIGS/CdS/i-ZnO/ZnO:Al/Al grid stack structure. The highest conversion efficiency of 9.65% with an open circuit voltage of 452.42 mV, short circuit current density of 32.16 mA cm2 and fill factor of 66.32% was obtained on a 0.755 cm2 cell area.     

Effect of oxygen partial pressure and transparent substrates on the structural and optical properties of ZnO thin films and their performance in energy harvesters

Zinc oxide (ZnO) thin films were deposited onto different substrates-tin-doped indium oxide (ITO)/glass, ITO/polyethylene naphthalate (PEN), ITO/polyethylene terephthalate (PET)-by the radio-frequency (RF) magnetron sputtering method. The effect of various O₂/(Ar+O₂) gas flow ratios (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) was studied in detail. ZnO layers deposited onto ITO/PEN and ITO/PET substrates exhibited a stronger c-axis preferred orientation along the (0002) direction compared to ZnO deposited onto ITO/glass. The transmittance spectra of ZnO films showed that the maximum transmittances of ZnO films deposited onto ITO/glass, ITO/PEN, and ITO/PET substrates were 89.2%, 65.0%, and 77.8%, respectively. Scanning electron microscopy (SEM) images of the film surfaces indicated that the grain was uniform. The cross-sectional SEM images showed that the ZnO films were columnar structures whose c-axis was perpendicular to the film surface. The test results for a fabricated ZnO thin film based energy harvester showed that its output voltage increased with increasing acceleration of external vibration.     

Reduction in secondary dendrite arm spacing in cast eutectic Al-Si piston alloys by cerium addition

The effects of Ce on the secondary dendrite arm spacing (SDAS) and mechanical behavior of Al-Si-Cu-Mg alloys were investigated. The reduction of SDAS at different Ce concentrations was evaluated in a directional solidification experiment via computer-aided cooling curve thermal analysis (CA CCTA). -The results showed that 0.1wt%-1.0wt% Ce addition resulted in a rapid solidification time, △T_S, and low solidification temperature, △T_S, whereas 0.1wt% Ce resulted in a fast solidification time, △ta-Al, of the α-Al phase. Furthermore, Ce addition refined the SDAS, which was reduced to approximately 36%. The mechanical properties of the alloys with and without Ce were investigated using tensile and hardness tests. The quality index (Q) and ultimate tensile strength of (UTS) Al-Si-Cu-Mg alloys significantly improved with the addition of 0.1wt% Ce. Moreover, the base alloy hardness was improved with increasing Ce concentration.     

溶胶-凝胶法制备掺铝氧化锌透明导电膜的正交实验研究

采用溶胶-凝胶法制备了掺铝氧化锌(ZnO：Al,ZAO)透明导电膜。对薄膜用X射线衍射(XRD)、扫描电镜(SEM)、四探针仪及紫外 可见分光光度计等分析测试手段进行了表征;通过正交实验探讨了溶胶浓度、铝离子的摩尔掺杂量以及退火温度等因素对其电阻率的影响。结果表明,薄膜电阻率随溶胶浓度、铝离子掺杂量的增加,呈现先减小后增大的趋势,并随退火温度的升高而减小,从而确定了制备ZAO透明导电膜的优化工艺条件为：溶胶浓度0.8mol/L,铝离子的掺杂量1.0%(摩尔分数),退火温度550℃。在优化工艺条件下制得的ZAO透明导电薄膜具有标准的ZnO纤锌矿结构,其电阻率为1.275×10^-3Ω·cm,平均透光率达84%。     

掺杂氧化锌薄膜的结构与刻蚀性能研究

本文利用中频反应磁控溅射方法,以Zn/Al (98 : 2) (wt. %)合金靶为靶材,制备了综合性能优良的铝掺杂氧化锌（ZnO:Al, AZO）透明导电薄膜. 研究了沉积工艺对薄膜结构、电学及光学性能的影响,分析了AZO薄膜的刻蚀性能以及所制备的绒面结构特性. 结果表明：基体温度对薄膜生长有较大的影响,当温度为150℃时,薄膜具有较好的晶化率,晶粒呈明显的柱状生长,晶界间结合紧密,薄膜的电阻率为4.6×10-4Ωcm. 镀膜时基体的移动速度会影响薄膜的晶体生长方式,但对其沉积速率影响不大. 具有择优生长特性、形成柱状晶组织的薄膜经稀盐酸腐蚀后,其表面呈规则的粗糙形貌;此结构有利于充分捕集太阳光,从而提高薄膜太阳电池的效率.     

不同衬底生长ZnO薄膜的结构与发光特性研究

采用射频磁控溅射方法分别在蓝宝石(Al2O3)(0001)和硅(100)衬底上制备ZnO薄膜．通过X-光衍射测量与分析表明两者都沿C轴方向生长，在Al2O3衬底上的ZnO薄膜结晶质量优于在Si衬底上的薄膜样品．然而，由原子力显微镜观测发现在Al2O3衬底上的薄膜晶粒呈不规则形状，且有孔洞，致密性较差；而在Si衬底上的ZnO薄膜表面呈较规则的三维晶柱，致密性好．光致发光测量表明，不同衬底上生长的ZnO薄膜表现出明显不同的发光行为．     

掺杂量对ZnO∶Tb复合薄膜的形貌和光学性能的影响

采用的两步法——先溅射成膜,后退火处理的工艺成功制备了ZnO:Tb复合薄膜,结合XRD、SEM、PL等手段研究了掺杂量对薄膜结构和形貌的影响.发现掺杂量为4.16%时,ZnO:Tb薄膜表面形成新奇T-A-ZnO结构以及不同直径和长度的螺纹状纳米棒;同时出现378 nm和387 nm两个较强的紫外发光峰,以及中心波长位于515 nm的强绿光峰.     

Study of phase separation in Ga25Se75 xTex chalcogenide thin films

The effects of composition and thermal annealing in between glass transition and crystallization temperature on the optical and structural properties of Ga25Se75-xTex were investigated. The glass transition and crystallization temperature of the synthesized samples was measured by non-isothermal DSC measurements. Amorphous thin films of Ga25Se75-xTex glasses were grown onto ultra clean glass/Si wafer (100) substrates using the vacuum evaporation technique. The effect of thermal annealing on the optical gap (Eg) for Ga25Se75-xTex thin films in the temperature range 358-388K is studied. As-prepared and annealed thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and optical absorption. Thermal annealing was found to be accompanied by structural effects, which in turn, lead to changes in the optical constants. The optical absorption coefficient (a) for as-deposited and thermally annealed films was calculated from the absorbance data. From the knowledge of absorption coefficient at different wavelengths, the optical band gap (Eg) was calculated for all compositions of Ga25Se75-xTex thin films before and after thermal annealing. Results indicate that allowed indirect optical transition is predominated in as-deposited and thermally annealed thin films. The influence of Te incorporation and thermal annealing in Ga25Se75-xTex thin films results in a gradual decrease in the indirect optical gap, this behaviorcan be explained as increased tailing. The decrease in optical band gap and an increase in absorption coefficient and extinction coefficient with thermal annealing can be attributed to transformation from amorphous to crystalline phase.     

I-V andC-V properties of TiO2 thin film by pulsed-laser reactive deposition

TiO-2 thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3 ambient. The current-voltage and capacitance-voltage of the Al/TiO-2/Si capacitors are measured. The results show that the dielectric constant of thin film after being annealed at 700℃ is found to be 46, and the border trap density and the interface state density at the TiO-2/p-Si interface are 1.8×10 12 cm -2 and 2×10 12 eV -1·cm -2, respectively. The conduction mechanisms of as-deposited films are also discussed.     

The evolution of microstructure and mechanical properties during high-speed direct-chill casting in different Al-Mg2Si in situ composites

The effect of high-speed direct-chill (DC) casting on the microstructure and mechanical properties of Al-Mg₂Si in situ composites and AA6061 alloy was investigated. The microstructural evolution of the Al-Mg₂Si composites and AA6061 alloy was examined by optical microscopy, field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The results revealed that an increase of the casting speed substantially refined the primary Mg₂Si particles (from 28 to 12 μm), the spacing of eutectic Mg₂Si (from 3 to 0.5 μm), and the grains of AA6061 alloy (from 102 to 22 μm). The morphology of the eutectic Mg₂Si transformed from lamellar to rod-like and fibrous with increasing casting speed. The tensile tests showed that the yield strength, tensile strength, and elongation improved at higher casting speeds because of refinement of the Mg₂Si phase and the grains in the Al-Mg₂Si composites and the AA6061 alloy. High-speed DC casting is demonstrated to be an effective method to improve the mechanical properties of Al-Mg₂Si composites and AA6061 alloy billets.     

A comparative study of four modified Al coatings on Ni3Al-based single crystal superalloy

Four modified Al diffusion coatings (Al, Cr–Al, Al–Si and Cr–Al–Si coatings) were prepared on Ni₃Al based single crystal superalloy IC20. The oxidation tests were carried out at 1 150 °C for up to 100 h. Cyclic hot corrosion tests were carried out at 950 °C for 50 h. The results indicate that the oxidation and corrosion resistances of IC20 alloy are improved significantly by the coatings, and both oxidation and hot corrosion resistances of the four coatings are rated in the order (from worst to best) of Cr–Al, Al, Cr–Al–Si, Al–Si coatings. It is found that the degradations of Al and Cr–Al coatings are very quick due to the serious inter-diffusion between the coatings and substrates. The inter-diffusion between Si-containing coatings and substrates is reduced since Si effectively retards the outward diffusion of Mo. The weak effects of Cr and benefit effects of Si to the oxidation and hot corrosion resistance were discussed. The hot corrosion degradation mechanism of superalloy IC20 was analyzed.     

Improvement of oxidation resistance of Nb–Ti–Si based alloys with additions of Al,Cr and B at different temperatures

The effects of Cr, Al and B addition on the microstructure and high-temperature oxidation behaviors (at 1200, 1250 and 1300 ?°C) of Nb–Ti–Si based alloys were investigated. The results showed that the addition of Cr stabilized α-Nb₅Si₃, while Al promoted the formation of β-Nb₅Si₃ and adding B promoted the formation of γ-Nb₅Si₃. Among the three elements, Al and Cr were beneficial to oxidation resistance at 1200 ?°C, and B was favorable to the oxidation resistance at 1300 ?°C. At 1250 ?°C, Al and B had the same effects on the improvement of oxidation resistance. The ratio of these alloying elements might play an important role in enhancing oxidation resistance. The oxidation resistance of the three kinds of silicides was compared, and the sequence was: γ-Nb₅Si₃> β-Nb₅Si₃> α-Nb₅Si₃. To predict the effects of the investigated alloying elements on the oxidation resistance of Nb–Ti–Si based alloys in a wider range of concentration, an artificial neural network (ANN) model was established, showing excellent accuracy and generalization ability. With the instructions of the ANN model, the oxidation resistance can be optimized with less additions of alloying elements.     

衬底温度对ZnO：Al薄膜结构和光透过性能的影响

利用超声喷雾热解方法以不同的沉积温度（450～530℃）在石英衬底上制备出具备较高光学质量的ZnO：Al（AZO）薄膜.通过X射线衍射谱（XRD）研究了薄膜的结构,用扫描电子显微镜（SEM）研究了薄膜的表面形貌,用紫外可见（UV）分光光度计对薄膜的光透过特性进行了测试分析.结果表明：所制备薄膜在可见波段具有较高透过率,并且沉积温度对AZO薄膜的结构和光透过性能有很大影响.在衬底温度为470℃时得到的AZO薄膜具有（002）择优取向,结晶质量最好、光透过率最高,在可见光区平均透过率达到85%以上.     

Al/SiO_2 周期迭层膜式微型偏光器中的Al膜层

对周期性Ａｌ／ＳｉＯ２迭层膜式微型偏光器中的Ａｌ膜层进行了研究．高消光比的迭层膜式微型偏光器的性能主要决定于Ａｌ膜层的介电常数．从理论上分析了影响Ａｌ膜层介电常数的因素及Ａｌ膜层的介电常数偏离体金属Ａｌ相应值的原因．Ａｌ膜层溅射沉积条件实验研究结果表明,沉积速率、膜层厚度及基底形貌的控制和选择是非常重要的     

氧离子束辅助激光淀积生长ZnO/Si的XPS研究

利用X射线光电子能谱深度剖析方法对ZnO/Si异质结构进行了分析，用该法可生长出正化学比的ZnO，不过生长的ZnO薄膜存在孔隙，工艺还有待进一步改进。     

超声波搅拌时间对原位自生Mg2Si/Al基复合材料凝固组织和力学性能的影响

为了研究铝基复合材料的凝固组织和力学性能,采用超声波搅拌的方法制备了原位自生Mg₂Si/Al基复合材料.利用X射线衍射仪(XRD)、金相显微镜(OM)和扫描电子显微镜(SEM)分析其微观形貌,并通过硬度检测和拉伸试验测试其力学性能.结果表明:超声波搅拌不但能够细化初生Mg₂Si颗粒,改变凝固组织形貌,而且具有除气除杂功能,二者共同提高了Mg₂Si/Al基复合材料的力学性能;经过超声波搅拌的Mg₂Si/Al基复合材料与未经过超声波搅拌的Mg₂Si/Al基复合材料相比,抗拉强度与伸长率总体呈上升趋势,其断口形貌均为准解理面.在超声时间为40 s时,抗拉强度和伸长率达到最大值,分别为201 MPa和5.63%,相比未超声处理的Mg₂Si/Al基复合材料的抗拉强度和伸长率,分别增长了139.29%和178.71%;复合材料的硬度先升高后降低,超声作用时间为30 s时硬度最佳,为116.96(HB).