Ca3Y2(Si3O9)2:Tb3+绿色荧光粉的光谱特性

采用高温固相法制备了Ca₃Y₂(Si₃O₉)₂: Tb³⁺绿色荧光粉,研究了材料的光学性能。X 射线衍射(XRD)结果显示,掺杂少量的Tb³⁺,并未影响Ca₃Y₂(Si₃O₉)₂材料 的晶相结构。Ca₃Y₂(Si₃O₉)₂:Tb³⁺ 荧光粉的激发光谱由较强的4f^75d1宽带吸收(200～300 nm )和较弱的4f-4f电子跃迁吸收 (300～500 nm)构成,主激发峰位于236nm。取波长分别为236、376和482nm的光 作为激发源时,发现样品的主发射峰均位于544 nm,对应Tb³⁺的⁵D 4→⁷F₅跃迁发射。以236nm 紫外光作为激发源,监测544nm主发射峰,随Tb³⁺浓度 的增大,Ca₃Y₂(Si ₃O₉)₂:Tb³⁺的荧光寿命逐渐减小,但在实验范围内并未出现浓度猝灭现象。     

太赫兹瞬态光谱研究La_(0.7)Ca_(0.3)MnO_3薄膜的温度相关相变（英文）

利用太赫兹瞬态光谱研究了La_(0.7)Ca_(0.3)MnO_3薄膜的热力学性质。La_(0.7)Ca_(0.3)MnO_3薄膜的金属-绝缘体相变温密切相关。研究发现在40～200 K的低温范围内,La_(0.7)Ca_(0.3)MnO_3薄膜的电导率可以用Drude模型拟合,在210～290 K的高温范围内可以用Drude-Lorentz模型拟合。     

基于La0.7Sr0.3FeO3的微结构乙醇气体传感器的研制

以La_0.7Sr_0.3FeO₃为敏感材料，设计制成了一种新型的共平面结构气体传感器.基于有限元分析软件Ansys对该传感器结构进行了优化设计.实验测得该传感器对于500ppm浓度乙醇气体的灵敏度为8.0，功耗为261mW，是同种敏感材料烧结型传感器功耗的2/3，响应时间约为1.5s，恢复时间约为2.5s，是一种功耗低、灵敏度高、稳定性好的微结构乙醇气体传感器.     

用溶胶-凝胶法制备的Cu2Bi2Cr2O8薄膜 及其光学和铁磁性能研究

以硝酸铜Cu(NO₃)₂·3H₂O、硝酸铬Cr(NO₃)₃·9H₂O、硝酸铋Bi(NO₃)₃·3H₂O和乙二醇为原料,利用溶胶-凝胶工艺在石英衬底上制备了纳米Cu₂Bi₂Cr₂O₈薄膜。通过X射线衍射(X-Ray Diffraction, XRD)和拉曼测试对样品进行了表征。结果表明,Cu₂Bi₂Cr₂O₈薄膜具有良好的光学特性,其禁带宽度为1.49 eV;在磁性测试方面,Cu₂Bi₂Cr₂O₈薄膜呈现出了良好的铁磁性。     

TiO2基染料敏化太阳能电池的表面修饰及性能研究

采用水热法制备TiO₂浆料,用La(NO₃)₃溶 液浸泡TiO₂薄膜获得修饰电极。用X射线光电子能谱(XPS) 和扫描电子显微镜(SEM)对修饰电极的主要成分及形貌进行表征的结果显示,电极薄膜分为 上下两层,表 面包覆层粒径较大,为La₂O₃颗粒;下层颗粒粒径较小,为TiO₂颗粒。电流-电压测 试结果显示,与修饰 前相比,用La(NO₃)₃溶液浸泡30min获得的膜电极性能最优,使 开路电压和短路电流分别提高了6.8%和 18.5%。电化学阻抗谱(EIS)测试结果表明,相同偏压下,TiO₂/La ₂O₃电极界面复合电阻比TiO₂要大,说明 La₂O₃包覆层在一定程度上抑制了界面的电子复合,改善了电池的光电化学性能。     

不同深宽比GaAs衬底的Al22O3/HfO2复合薄膜材料原子层沉积及能谱分析

利用热原子层沉积（Atomic Layer Deposition, ALD）技术在不同深宽比GaAs衬底上进行了Al2₂O₃/HfO₂复合薄膜的沉积。通过对其表面和能谱进行分析发现,沉积温度对复合薄膜的摩尔比具有较大的影响。随着深宽比的增大,其沉积表面和沟槽内会出现残留物;随着ALD沉积温度的上升,其沉积表面和沟槽内的残留物减少,摩尔比趋向均匀。当深宽比为2.2并利用150 ℃的低沉积温度时,表面及底面基本无残留物。但当深宽比为4.25时,150 ℃沉积明显有大量残留物。只有当温度升高到300 ℃时,表面和沟槽里复合薄膜的残留物才被明显消除。ALD技术可以实现各种器件结构的全方位钝化,这是其他化学气相沉积法无法比拟的。     

Mn0.1Ti0.9O2-δ稀磁半导体薄膜的MBE生长及表征

采用OPA-MBE方法在SrTiO3(STO)衬底上成功制备了Mn_0.1Ti_0.9O_2-δ(MTO）稀磁半导体薄膜. 利用X射线衍射仪、X射线光电子能谱仪、紫外可见光分度计以及直流四探针测试仪研究了薄膜的晶体结构、化学组成、光吸收和电荷输运性质. MTO薄膜具有锐钛矿和金红石的混合相，光吸收带边界发生“红移”，电荷输运性质明显提高，室温环境下电阻率仅为37.5Ω·m.     

CaBi2Ta2O9基压电陶瓷改性研究

该文采用传统固态反应法制备了Ca_1-x(Li_0.5Ce_0.4Pr_0.1)_xBi₂Ta₂O₉(x为摩尔分数)陶瓷,研究了(Li_0.5Ce_0.4Pr_0.1)²⁺复合离子不同掺杂浓度对陶瓷结构和电学性质的影响。结果表明,在选定浓度范围内,(Li_0.5Ce_0.4Pr_0.1)²⁺复合离子改善了CaBi₂Ta₂O₉基陶瓷的压电活性与高温下的直流电阻等特性。当x=0.08时,陶瓷具有最佳综合性能,即压电常数d₃₃=10.3 pC/N,居里温度TC=928 ℃,直流电阻率ρ=1.12×10⁶ Ω·cm(650 ℃),介电损耗tan δ=0.026(1 MHz,650 ℃)。     

用热蒸发法制备的Cu2ZnSnS4 薄膜的光电性能

在室温下用真空热蒸发法在玻璃基片上制备Sn/Cu/ZnS 前躯体膜层,然后对其在550C 下在硫气氛中硫化3小时以制得Cu₂ZnSnS₄ (CZTS) 多晶薄膜。对该薄膜进行X射线衍射（XRD）、能量色散X射线光谱（EDX）、紫外可见近红外分光光度计、霍尔测量系统和3D光学显微镜等分析测试。实验结果表明,当[Cu]/([Zn] [Sn]) =0.83和[Zn]/[Sn] =1.15时,该CZTS薄膜在光子能量范围在1.5 - 3.5 eV 时其吸收系数大于4.010₄cm_-1 ,直接带隙为1.47 eV。其载流子浓度、电阻率和迁移率分别为7.9710₁₆ cm_-3, 6.06 Ω.cm, 12.9 cm₂/(V.s), 导电类型为p型。因此,所制备出的CZTS 薄膜适合作为太阳电池的吸收层材料。     

CaHPO4:Tb3+纳米晶的相演变与发光性能研究

以无水乙醇作反应溶液,采用室温共沉淀,合成 了CaHPO₄:Tb³⁺绿色荧光粉。用X射线衍射(XRD)、 扫描电镜(SEM)、荧光(PL)光谱、热重(TG)和差示扫描量热(DSC)等分别对所得样品的相结构、形貌、发光 性能以及热稳定性进行研究。研究结果表明,在室温条件下,得到了纯三斜相CaHPO₄:Tb ³⁺;当烧结温度为 400℃时,开始出现相结构转变;温度升高到500℃以上时,晶相完全转变为纯四方晶系Ca₂P₂O₇,但样 品的形貌变化很小,都为分散性比较好、尺寸分布比较均匀的纳米颗粒。同时,利用激发光 谱和发射光谱 研究了Tb³⁺在CaHPO₄和Ca₂P₂O₇基质中的发光性能,在波长为370nm紫外光的激发下,都观察到Tb³⁺的特 征跃迁(⁵D₄→⁷FJ,J=3~6),其中以⁵D₄→⁷F₅ 跃迁发射(544nm)为主,而且CaHPO₄:Tb³⁺的发光强度要明 显强于Ca₂P₂O₇:Tb³⁺。     

Excellent performance of gas sensor based on In2O3-Fe2O3 nanotubes

In₂O₃-Fe₂O₃ nanotubes are synthesized by an electrospinning method. The as-synthesized materials are characterized by scanning electron microscope and X-ray powder diffraction. The gas sensing results show that In₂O₃-Fe₂O₃ nanotubes exhibit excellent sensing properties to acetone and formaldehyde at different operating temperatures. The responses of gas sensors based on In₂O₃-Fe₂O₃ nanotubes to 100 ppm acetone and 100 ppm formaldehyde are 25 (240℃) and 15 (260℃), and the response/recovery times are 3/7 s and 4/7 s, respectively. The responses of In₂O₃-Fe₂O₃ nanotubes to 1 ppm acetone (240℃) and formaldehyde (260℃) are 3.5 and 1.8, respectively. Moreover, the gas sensor based on In₂O₃-Fe₂O₃ nanotubes also possesses an excellent selectivity to acetone and formaldehyde.     

New TIT capacitor with ZrO2/Al2O3/ZrO2 dielectrics for 60 nm and below DRAMs

New ZrO₂/Al₂O₃/ZrO₂ (ZAZ) dielectric film was successfully developed for DRAM capacitor dielectrics of 60 nm and below technologies. ZAZ dielectric film grown by ALD has a mixture structure of crystalline phase ZrO₂ and amorphous phase Al₂O₃ in order to optimize dielectric properties. ZAZ TIT capacitor showed small Tox.eq of 8.5 Å and a low leakage current density of 0.35 fA/cell, which meet leakage current criteria of 0.5 fA/cell for mass production. ZAZ TIT capacitor showed a smaller cap leak fail bit than HAH capacitor and stable leakage current up to 550 °C anneal. TDDB (time dependent dielectric breakdown) behavior reliably satisfied the 10-year lifetime criteria within operation voltage range.     

共沉淀法制备Y2O2SO4:Eu3+荧光粉及其光致发光研究

采用商业Y(NO3)3·6H2O、Eu(NO3)3·6H2O、(NH4)2SO4和NaOH为实验原料,通过共沉淀法制备了Y2O2SO4:Eu3+荧光粉。利用热分析(DTA-TG-DTG)、傅里叶变换红外(FT-IR)光谱、X射线衍射(XRD)、扫描电子显微镜(SEM)和光致发光(PL)光谱等手段对合成的粉体进行了表征。结果表明,当(NH4)2SO4引入到反应体系中时,前驱体具有非晶态结构,且在空气气氛中800℃煅烧2h能转化为单相的Y2O2SO4粉体,该Y2O2SO4粉体呈准球形,粒径范围分布在0.5~1.0μm之间,团聚较严重。PL光谱分析表明,在270nm紫外光激发下,Y2O2SO4:Eu3+荧光粉呈红光发射,主发射峰位于620nm,归属于Eu3+的5D0→7F2跃迁。Eu3+的猝灭浓度是5 mol%,其对应的荧光寿命为1.22 ms。另外,当(NH4)2SO4未引入到反应体系中时,采用类似的方法合成了Y2O3:Eu3+荧光粉,并对Y2O2SO4:Eu3+和Y2O3:Eu3+荧光粉的PL性能进行了比较。     

CH3NH3PbI3/p-Si异质结的光电特性研究

利用一步溶液法在p型Si衬底上生长有机/无机杂化钙钛矿CH3NH3PbI3薄膜,构成CH3NH3PbI3/p-Si异质结。利用原子力显微镜(AFM)、扫描电子显微镜(SEM)对薄膜形貌和结构进行表征,通过无光照和有光照条件下的电流-电压(I-V)、电容-电压(C-V)测试对异质结的光电特性进行研究。I-V测试结果显示CH3NH3PbI3/p-Si异质结具有整流特性,正反偏压为±5V时,整流比大于70,并在此异质结上观察到了光电转换现象,开路电压为10mV,短路电流为0.16uA。C-V测试结果显示Ag/CH3NH3PbI3/p-Si异质结具有与MIS(金属-绝缘层-半导体)结构相似的C-V特性曲线,与理想MIS的C-V特性曲线相比,异质结的C-V曲线整体沿电压轴向正电压方向平移。C-V特性曲线的这种平移表明Ag/CH3NH3PbI3/p-Si异质结界面存在界面缺陷,CH3NH3PbI3层也可能存在固定电荷。这种界面缺陷是导致CH3NH3PbI3/p-Si异质结开路电压的大幅度降低的重要原因。此外,CH3NH3PbI3薄膜的C-V测试结果显示其具有介电非线性特性,其介电常数约为4.64。     

具有界面依赖光致发光的双层WS2/Ga2O3异质结的能带工程(英文)

利用垂直WS₂/Ga₂O₃异质结构中异质界面诱导了反常的光致发光(PL)发射。垂直堆栈的WS₂/Ga₂O₃异质界面使其形成了II型能带结构,导致与Ga₂O₃层接触的底层WS₂的PL强度下降。而异质界面的强耦合作用也影响了双层WS₂中的同质层间相互作用,使得上层WS₂出现反常的PL增强。这种堆栈新型二维异质结构为定制目标能带结构并控制其光子和电子行为提供一种新的手段。     

In0.53Ga0.47As表面氮化和硫钝化对其Al/Al2O3/InGaAs MOS电容特性的影响

本文通过对比频散特性和滞回特性,计算界面态密度D_it和有效边界缺陷密度ΔN_bt,分析界面缺陷和漏电流等方法,系统的研究了In_0.53Ga_0.47As表面氮化和硫钝化对其Al/Al₂O₃/InGaAs结构MOS电容特性的影响。实验结果表明,这两种方法都能够在InGaAs表明形成一层界面钝化层。相比较于未处理的样品,经过氮气等离子体处理的样品表现出较好的界面特性,得到了最小的积累区频散、滞回电压,以及良好的I-V性能。经过(NH₄)₂S_x处理的样品则获得了最小的平带电压区频散以及最低的界面态密度Dit=2.6E11cm_-2eV_-1.     

Effects of annealing schedule on orientations of Bi3.2Nd0.8Ti3O12 ferroelectric films prepared by metalorganic solution deposition

Fatigue-free Bi_3.2Nd_0.8Ti₃O₁₂ ferroelectric thin films were successfully prepared on p-Si(1 1 1) substrate using metalorganic solution deposition process. The orientation and formation of thin film under different annealing schedules were studied using XRD and AFM. XRD analysis indicated that (2 0 0)-oriented films with degree of orientation of I₍₂₀₀₎/I₍₁₁₇₎ = 2.097 and 0.466 were obtained by preannealing the film at 400 °C for 10 min followed by rapid thermal annealing at 700 °C for 3 min, 10 min and 20 min, respectively, (0 0 8)-oriented film with degree of orientation of I₍₀₀₈₎/I₍₁₁₇₎ = 1.706 were obtained by rapid thermal annealing the film at 700 °C for 3 min without preannealing, and (0 0 8)-oriented film with degree of orientation of I₍₀₀₈₎/I₍₁₁₇₎ = 0.719 were obtained by preheating the film from room temperature to 700 °C at 20 °C/min followed by annealing for 10 min. The a-axis and c-axis orientation decreased as increase in annealing time due to effects of (1 1 1)-oriented substrate. AFM analysis further indicated that preannealing at 400 °C for 10 min followed by rapid thermal annealing at 700 °C for 3 min resulted in formation of platelike crystallite parallel to substrate surface, however rapid thermal annealing at 700 °C for 3 min without preannealing resulted in columnar crystallite perpendicular to substrate surface.     

Study of thick film Ni(1−x)CoxMn2O4,(0?x?1) using overlay technique on thick film microstrip ring resonator

The effect of thick film Ni_(1−x)Co_xMn₂O₄ in-touch overlay on the X band resonance characteristics of thick film microstrip ring resonator is studied. The thick film overlay decreases the resonance frequency and increases the peak output. From the frequency shift the dielectric constant of the thick film Ni_(1−x)Co_xMn₂O₄ has been calculated. For the first time Ag thick film microstrip ring resonator has been used to study thick film Ni_(1−x)Co_xMn₂O₄ in the X band.     

用于非易失性相变存储器中Si2Sb2Te5在CF4/Ar等离子体下的反应离子刻蚀

Phase change random access memory（PCRAM） is one of the best candidates for next generation nonvolatile memory,and phase change Si₂Sb₂Te₅ material is expected to be a promising material for PCRAM.In the fabrication of phase change random access memories,the etching process is a critical step.In this paper,the etching characteristics of Si₂Sb₂Te₅ films were studied with a CF₄/Ar gas mixture using a reactive ion etching system.We observed a monotonic decrease in etch rate with decreasing CF4 concentration,meanwhile,Ar concentration went up and smoother etched surfaces were obtained.It proves that CF4 determines the etch rate while Ar plays an important role in defining the smoothness of the etched surface and sidewall edge acuity.Compared with Ge₂Sb₂Te₅, it is found that Si₂Sb₂Te₅ has a greater etch rate.Etching characteristics of Si₂Sb₂Te₅ as a function of power and pressure were also studied.The smoothest surfaces and most vertical sidewalls were achieved using a CF₄/Ar gas mixture ratio of 10/40,a background pressure of 40 mTorr,and power of 200 W.