退火温度对银-二氧化硅核壳(Ag@SiO2/TiO2)薄膜结构，光学特性以及光催化性能的影响

局部表面等离子共振广泛应用于光催化和太阳能 电池等领域。采用电子束和热沉积技 术,在融石英和Si片上制备了Ag@SiO₂/TiO₂薄膜。在300 ℃,400 ℃,500 ℃,600 ℃ 温度下,薄膜在空气氛围下退火2h。采用拉曼光谱仪,紫外-可见分光光度 计(UV-Vis)等手段对微结构,光学性能等特性进行了表征。利用能谱仪测定了元素成分及含 量。考察了薄膜在水溶液中降解甲基橙的光催化活性。结果表明:Ag@SiO₂/TiO₂薄膜具有优 异的光催化性能。测试结果表明:在250℃下制备的TiO₂薄膜为无定形结构;在本实验条 件下,随着退火温度的升高,薄膜呈锐钛矿结构;锐钛矿相表现出了更好的光催化性能。     

银纳米颗粒修饰TiO2薄膜的结构,光学及光催化性能

采用电子束沉积技术在石英玻璃、硅片基板上沉积了TiO₂薄膜,利用热蒸发技术在TiO₂薄膜表面沉积了不同厚度的Ag膜,研究了Ag膜厚度对TiO₂薄膜结构、形貌、光学和光催化 性能的影响。利 用紫外-可见分光光度计(UV-VIS)、X射线衍射仪(XRD)、冷场发射电子显微镜(SEM)对沉积 后的薄膜分别 进行光学、结构、形貌分析。利用能谱仪测定了元素成分及含量。用光催化降解亚甲基橙(M O)的速率评 价了合成的Ag-TiO₂的光催化性能。结果表明:Ag纳米粒子在TiO₂表面均匀分布;制备 的Ag修饰多孔TiO₂纳米薄膜具有优异的光催化性能。测试结果表明:在250 ℃下制备的T iO₂薄膜为无定形结构;随着Ag膜厚度 的增加,样品的光催化活性提高。当Ag膜厚度为3.7 nm时,光催化活 性最高;与纯TiO₂相比,Ag-TiO₂具有更高的光催化活性。     

退火Cu2O薄膜的结构及光学特性

采用射频(RF)磁控溅射单质金属铜(Cu)靶, 在O₂和Ar的混合气氛下制备了Cu₂O薄 膜,并在N₂气氛下对预沉积的Cu₂O薄膜进行快速光热退火(RTA)处理,研究了 衬底温度及退火温度对Cu₂O 薄膜的生长行为、物相结构、表面形貌及光学性能的影响。结果表明,衬底温度在300℃以 下预沉积的Cu₂O薄膜 为非晶薄膜,退火处理对Cu₂O薄膜的结晶行为有明显影响,在N₂气氛下对Cu₂O薄膜进 行退火处理不影响薄膜的物 相结构;预沉积和退火Cu₂O薄膜在650nm以下波长范围内均有较强 吸收,吸收强度随退火温度的增加而增强,薄 膜在400nm以下波长范围内出现两个由缺陷引起的中间带(IB)吸收行 为,快速热退火处理不能减少或消除薄膜沉积 过程中形成的缺陷态;退火处理影响薄膜的光学带隙Eg,预沉 积薄膜经600℃退火处理,E_g值增大了 0.26eV。     

Ag含量对TiO2薄膜光学性能和光催化性能影响

为了研究Ag含量对光催化效率的影响,采用电子 束沉积方法制备了Ag-TiO₂光催化剂,分别用X射 线衍射仪(XRD),紫外－可见光谱仪(UV-Vis),电子扫描显微镜(SEM),原子力显微镜 (AFM),X射线电子能谱 仪(XPS)等手段对晶体结构,光学性能和薄膜形貌以及元素价态元素组成等进行了表征.利用 太阳光,以甲基 橙(MO)为模型,分析了不同Ag含量薄膜的光催化效率.结果显示:Ag是以Ag⁰存在,Ag均匀而 牢固的分布在 TiO₂材料上;在300℃温度下,所形成的薄膜为无定形结构;沉积适 量的银,可以提高纳米二氧化钛光催化活性。     

低温处理的TiO2纳米颗粒薄膜作为缓冲层的有机光伏电池

通过溶胶凝胶法(sol-gel)合成了TiO₂纳米颗 粒(NPs),制备了结构为 ITO/PEDOT:PSS/P3HT:PCBM/TiO₂/Al的有机太阳能电池(OSC)器件。通过优化阴极缓冲 层TiO₂NPs的 热处理温度,考察了温度以及溶剂对TiO₂NPs薄膜的光学性能、形貌结构和电学 性能的影响,并研究了其对OSC性能的影响及作用机理。实验发现,TiO₂NPs处理温度 为80℃时,器件 的效率达到了2.52%。相对于参比器件,器件的光电转换效率(PCE) 、填充因子(FF)分别提高了60%、64.7%。     

（英）沉积温度对脉冲激光沉积法在YSZ (100)衬底上生长的Mn1.56Co0.96Ni0.48O4尖晶石薄膜结构、电学和磁学性能的影响

在YSZ（100）衬底上,采用脉冲激光沉积法在500℃至700℃的不同沉积温度下生长出尖晶石结构的Mn_1.56Co_0.96Ni_0.48O₄（MCNO）薄膜.由于沉积温度是制备高质量薄膜的重要因素,本文研究了MCNO薄膜结构、电学和磁学性能随沉积温度的变化.通过对X射线衍射图和原子力显微镜图像的分析,发现MCNO薄膜的结晶与沉积温度有很大关系.随着沉积温度的升高,MCNO薄膜的电阻率呈V型变化,其导电过程可以用小极化子跳跃机理来描述.同时,随温度变化的磁化曲线表明所有样品都显示出从铁磁性到顺磁性的转变,且沉积温度为600℃的MCNO薄膜具有216 K的高居里温度.以上研究结果表明,在600℃沉积的MCNO薄膜具有适用于热敏电阻器件和多功能异质结所需的良好性能.     

Al/N共掺杂TiO2薄膜的制备及光学性能

采用溶胶-凝胶旋涂法(Sol-Gel Spin-Coating Method)制备了Al掺杂量为3.00at%,N掺杂量分别为6.00at%,7.00at%,8.00at%和9.00at%的Al/N共掺杂TiO₂薄膜样品。对样品测试的结果表明,共掺杂样品依旧保留了TiO₂的基本结构,并且Al/N共掺杂样品的晶粒尺寸有不同程度的减小,使样品表面得以修饰,变得更加均匀、平整。共掺杂样品吸收边都出现了不同程度的红移,在紫外光区以及可见光区的吸光性都有所增强。N掺杂量为7.00at%时,(101)衍射峰值最大,峰型最尖锐,所得到的TiO₂薄膜的光学性能最好。共掺杂后的样品与本征TiO₂相比带隙值都有所减小,且最小值为2.873eV。以上结果表明Al/N共掺杂TiO₂薄膜使其光学性能得到了改善。     

氮气流量对磁控溅射C掺杂TiO2薄膜光学性能的影响

采用磁控溅射法制备了C掺杂TiO₂薄膜,并研究了氮气引入溅射过程对薄膜光学性能的影响。利用X射线衍射仪、拉曼光谱仪、X射线光电子能谱仪、分光光度计和原子力显微镜分析了不同氮气流量下薄膜的微结构、元素价态、透光性能和表面形貌。结果表明,沉积的薄膜主要是非晶结构,拉曼光谱中存在少量锐钛矿相,且随着氮气流量增大,锐钛矿特征峰强度减弱,意味着晶粒出现细化。当氮气流量增大为4cm³/min时,C掺杂TiO₂薄膜内氮元素含量为3.54%,其光学带隙从3.29eV变化至3.55eV,可见光区的光学透过率明显提高。可见改变氮气流量可实现对C掺杂TiO₂薄膜光学带隙和光吸收率的有效调控。     

磁控溅射法在6H-SiC衬底上制备β-FeSi2薄膜

采用磁控溅射FeSi₂、Si靶加后续退火法在6H-SiC(0001)衬底上成功制备了β-FeSi₂薄膜.采用XRD、SEM、AFM和Raman等测试手段对β-FeSi₂薄膜的结构及形貌等特性进行了表征。XRD结果表明,当退火温度从500℃增加到900℃时,溅射的非晶FeSi₂薄膜逐步相变为β-FeSi₂薄膜,且其最佳的退火温度为900℃;SEM测试结果表明β-FeSi₂薄膜表面较为平整、致密,β-FeSi₂/6H-SiC界面清晰陡峭,薄膜表面粗糙度(RMS)为0.87nm;β-FeSi₂薄膜的光学带隙为0.88eV。由此获得了在6H-SiC衬底上制备多晶β-FeSi₂薄膜的最佳工艺条件。     

磁控溅射法制备LiTaO3薄膜及其结晶性能研究

用射频磁控溅射法在Pt/Ti/SiO₂/Si(100)基片上沉积了LiTaO₃薄膜,并在氧气气氛中不同温度下进行退火。采用SEM、XRD、XPS等表征方法分析了薄膜的结晶性能、各元素化学价态和元素原子百分比。结果表明,经700℃退火处理1h得到的薄膜结晶性能最好,在(104)晶向上具有强烈的择优取向性。薄膜退火温度的升高导致薄膜中Li空位缺陷和O空位缺陷减少。研究表明,薄膜中O/Li的原子比对结晶性能有着非常明显的影响,原子值越接近晶体化学计量比,结晶性能越好。     

Nickel silicidation techniques for strained Si1?xGex, Si1?x?yGexCy, and Si1?yCy alloys material-device applications

A nickel silicide process for Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy materials compatible with Si technology has been developed. Low-resistivity-phase (12–20 μΘ cm) nickel silicides have been obtained for these alloys with different low sheet-resistance temperature windows. The study shows that thin (15–18 nm) silicide layers with high crystalline quality, smooth silicide surface, and smooth interface between silicide and the underlying material are achievable. The technique could be used to combine the benefits of Ni silicide and Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloys. The technique is promising for Si or Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy-based metal-oxide semiconductor, field-effect transistors (MOSFETs) or other device applications.     

YBa2Cu3-xZnxO7薄膜红外探测器的研究

在对红外探测器进行理论分析的基础上,设计并研制了液氮温度下的Yba2Cu3-xZnxO7薄膜红外探测器,系统地测试了器件的特征参数.最好的结果为:对于波长为10μm,调制频率为f=500Hz,带宽为Δf=1Hz的红外输入辐射Rv(500,10,1)=3587V/W,NEP(500,10,1)=6.5×10-12W/Hz1/2,D*(500,10,1)=7.2×1012cmHz1/2/W,τ(500,10,1)=1.2ms.     

SiNx/SiOxNy叠层结构防潮能力的研究

研究了等离子体增强化学气相沉积(PECVD)工艺参数对SiN_x及SiO_xN_y防潮能力的影响,并测试了SiN_x/SiO_xN_y叠层薄膜的水汽渗透速率(WVTR)。实验结果表明:单层SiN_x薄膜和SiO_xN_y薄膜都存在临界厚度,当膜厚大于临界值时,继续增大厚度不会明显改善薄膜的WVTR。当沉积温度从50℃提高到250℃,SiN_x薄膜的WVTR从0.031g/(m²·day)降至0.010g/(m²·day)。SiO_xN_y沉积时,增大N₂O通入量对薄膜的WVTR影响不明显,但可以有效改善薄膜的弯曲性能。最后,4个SiN_x/SiO_xN_y叠层膜的WVTR下降到了4.4×10-4g/(m²·day)。叠层膜防潮能力的显著提升归因于叠层结构可以有效解耦层与层之间的缺陷,延长水汽渗透路径。     

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.     

Comparison between Pt/TiO2/Pt and Pt/TaOX/TaOY/Pt based bipolar resistive switching devices

Nonvolatile memories have emerged in recent years and have become a leading candidate towards replacing dynamic and static random-access memory devices. In this article, the performances of TiO₂ and TaO₂ nonvolatile memristive devices were compared and the factors that make TaO₂ memristive devices better than TiO₂ memristive devices were studied. TaO₂ memristive devices have shown better endurance performances (10⁸ times more switching cycles) and faster switching speed (5 times) than TiO₂ memristive devices. Electroforming of TaO₂ memristive devices requires~4.5 times less energy than TiO₂ memristive devices of a similar size. The retention period of TaO₂ memristive devices is expected to exceed 10 years with sufficient experimental evidence. In addition to comparing device performances, this article also explains the differences in physical device structure, switching mechanism, and resistance switching performances of TiO₂ and TaO₂ memristive devices. This article summarizes the reasons that give TaO₂ memristive devices the advantage over TiO₂ memristive devices, in terms of electroformation, switching speed, and endurance.     

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.     

Electrodepositing ZnxMnyOz alloys from zinc oxide to manganese oxide

Electrodeposition has emerged as a practical and simple method to synthesise semiconductor materials under different forms, thin films or nanostructured layers. This work reports on the cathodic electrodeposition of ZnMnO thin layers using both zinc and manganese chlorides as precursors. The composition of thin films can be varied from binary zinc oxide to manganese oxide varying the Mn/(Mn+Zn) ratio between 0 and 1. The composition of Zn_xMn_yO_z films was obtained by energy dispersive spectroscopy. Zn_1−xMn_xO films with Mn/Zn ratio less than 10% exhibit a crystalline wurtzite structure typical of ZnO fully oriented in the (0 0 2) direction. Higher Mn content leads to deformation of the ZnO lattice and the wurtzite structure is no longer maintained. X-ray photoelectron spectroscopy points out that Mn₃O₄ tends to be deposited when a high Mn/Zn ratio is used in the starting solution. Magnetic measurements on films with Mn/(Zn+Mn) ratio near 1 reveal magnetic characteristics similar to Mn₃O₄ compounds. The transmission spectra of Zn_xMn_yO_z show the typical absorption edge of crystalline ZnO while the wurtzite structure is maintained and it shifts to higher wavelengths when Mn content increases.     

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。     

Investigation of Ta2O5/SiO2/4H-SiC MIS capacitors

Tantalum pentoxide (Ta₂O₅) deposited by pulsed DC magnetron sputtering technique as the gate dielectric for 4H-SiC based metal-insulator-semiconductor (MIS) structure has been investigated. A rectifying current-voltage characteristic was observed, with the injection of current occurred when a positive DC bias was applied to the gate electrode with respect to the n type 4H-SiC substrate. This undesirable behavior is attributed to the relatively small band gap of Ta₂O₅ of around 4.3 eV, resulting in a small band offset between the 4H-SiC and Ta₂O₅. To overcome this problem, a thin thermal silicon oxide layer was introduced between Ta₂O₅ and 4H-SiC. This has substantially reduced the leakage current through the MIS structure. Further improvement was obtained by annealing the Ta₂O₅ at 900 °C in oxygen. The annealing has also reduced the effective charge in the dielectric film, as deduced from high frequency C-V measurements of the Ta₂O₅/SiO₂/4H-SiC capacitors.     

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。