Al_2O_3过渡层厚度对AZO薄膜性能的影响研究

采用磁控溅射法,在预先沉积了Al2O3过渡层的玻璃衬底上制备了性能优良的AZO薄膜。借助XRD、AFM、四探针仪和分光光度计对AZO薄膜的结构、表面形貌以及电学和光学性质进行了表征,并研究了Al2O3过渡层厚度对AZO薄膜性能的影响。结果表明:Al2O3过渡层的添加对AZO薄膜的表面形貌有一定影响;AZO薄膜的结晶质量随着过渡层厚度的增加先上升后下降;AZO薄膜的电阻率因过渡层的添加而明显降低,特别是在AZO薄膜较薄时;在添加了1～3 nm厚的过渡层后,160 nm厚的AZO薄膜的电阻率下降了44%左右;AZO薄膜的可见光透射率和光学带隙基本不受过渡层影响。     

ZnO缓冲层和退火处理对MgO薄膜结构的影响

采用直流反应磁控溅射法在Si衬底上引入ZnO缓冲层制备了沿(200)晶面择优取向生长的MgO薄膜,然后分别采用快速退火和常规退火两种不同的方式对MgO薄膜进行晶化处理。利用X射线衍射仪(XRD)以及原子力显微镜(AFM)研究了ZnO缓冲层以及两种不同的退火方式对MgO薄膜的结构和形貌的影响。结果表明:具有合适厚度的ZnO缓冲层可以显著地提高MgO薄膜的结晶质量。另外,与快速退火相比,常规退火处理后得到的MgO晶粒均匀圆润,有着较大的(200)衍射峰强度以及较小的表面粗糙度。     

缓冲层对太阳电池用ZnO:B薄膜结构及其光电性能的影响

通过优化ZnO缓冲层(buffer layer),有效地改善了由金属有机化学气相沉积(MOVCD)法制备的ZnO:B薄膜的光电特性。结果表明,"富氧"的缓冲层有效增加了ZnO:B-TCO的近红外区域透过率,使其更适应宽光谱薄膜太阳电池的发展要求。经过优化的ZnO:B,"类金字塔"状晶粒尺寸约300～500nm,波长550nm处绒度(haze)为10.8%,薄膜电子迁移率为20.7cm2/Vs,电阻率为2.14×10-3Ω.cm,载流子浓度为1.41×1020cm-3,且在400～1 500nm波长范围内的平均透过率为83%(含2mm厚玻璃衬底)。     

PLD法制备基于缓冲层的ZnO薄膜及纳米棒研究进展

综述了脉冲激光沉积(PLD)法基于缓冲层制备ZnO薄膜及ZnO纳米棒的研究进展,分析了缓冲层对于生长高质量ZnO薄膜及纳米棒的作用,得到结论:引入缓冲层可以减少沉积物与衬底晶格失配以及热膨胀系数不匹配的问题。     

AZO种子层朝向对ZnO纳米棒形貌和发光特性的影响

在水平管式炉中,采用热蒸发锌粉的方法,在镀有掺铝氧化锌(AZO)薄膜的石英基片上制备了大量高密度的ZnO纳米棒,AZO膜面分别正对和背对锌源。利用扫描电子显微镜、X射线衍射仪以及荧光光谱仪分析AZO膜面朝向对ZnO纳米棒的形貌、微结构及光学性能的影响。结果表明,不同朝向的AZO膜面上所生长的纳米棒具有相似的形貌和微结构。保温时间10min样品的氧空位的缺陷态发光为绿光,强度较强;保温时间15min样品的纳米棒长度较长、相对垂直衬底,其近带边发光较强,氧间隙的缺陷态发光较弱。正对锌源衬底上且保温时间15min样品的近带边发光最强,且缺陷态发光最弱。     

Al薄膜对(002)ZnO/Al/Si结构基片中ZnO薄膜特性影响的实验研究

采用射频磁控溅射法沉积制备了(002)ZnO/A l/Si复合结构。研究了Al薄膜对(002) ZnO/Al/Si复合结构的声表面波器件(SAWD)基片性能影响以及当ZnO 薄膜厚度一定时的Al膜最佳厚度。采用X射线衍射(XRD)对Al和ZnO薄膜进行了结构表征 ,采用 扫描电镜(SEM)对ZnO薄膜进行表面形貌表征,并从薄膜生长机理角度进行了分析。结果 表明,加Al薄膜有利于ZnO薄膜按(002)择优取向生长,并且ZnO 薄膜的结晶性能提高;与(002)ZnO/Si结构基片相比,当Al薄膜 厚为100nm时,(002)ZnO/Al/Si结构中ZnO薄 膜的机电耦合系数提高 了65%。     

ZnO过渡层对BiFeO_3薄膜铁电性能的影响

采用溶胶–凝胶法,在Pt(111)/Ti/SiO2/Si(100)衬底上采用逐层退火工艺制备了BFO(BiFeO3)、ZnO/BFO和ZAO(掺铝氧化锌)/BFO薄膜,研究了ZnO、ZAO过渡层对BFO薄膜晶相以及铁电、漏电和介电性能的影响。结果表明:与BFO薄膜相比,ZnO/BFO薄膜的表面更加致密、平整,结晶性更好,双剩余极化强度(2Pr)有非常大的提高,漏电和介电性能也均有改善。ZAO/BFO薄膜的铁电性能比ZnO/BFO薄膜的铁电性能差,这与ZAO的导电性强于ZnO有关。     

LiNbO_3/ZnO:Al集成结构的外延生长及电性能研究

采用脉冲激光沉积(PLD)法在蓝宝石衬底上先后外延生长了ZnO:Al(ZAO)和LiNbO3(LN)薄膜。通过X射线衍射分析(XRD)可知二者之间的外延关系为:LN(001)//ZAO(001)、LN[110]//ZAO[110]、LN[100]//ZAO[120]。制备了Au/LN/ZAO和ZAO/LN/ZAO两种电容器结构,对其进行了电流-电压(J-E)测试和铁电(P-E)分析,结果表明:LN/ZAO集成结构具有整流作用,ZAO/LN/ZAO结构表现出较好的绝缘性能,所制备的LN薄膜在室温下的剩余极化强度(Pr)约为1×10–6C/cm2,温度的升高能够促进电畴的翻转,使Pr增加为3×10–6C/cm2。     

掺铝氧化锌陶瓷靶材的制备及其薄膜的光学性能

以Al(NO3)3.9H2O和ZnO粉体为原料,采用常压烧结方法制备了高致密度和高导电性的ZnO:Al(AZO)陶瓷靶材。研究了烧结温度对AZO靶材微观结构、相对密度和电性能的影响。当Al和Zn的摩尔比为3:100,烧结温度为1 400℃时,所制AZO靶材的致密度达96%,电阻率为2.5×10–2.cm。以烧结温度为1400℃的AZO陶瓷靶为靶材并通过直流磁控溅射在玻璃基片上制备出了高度c轴择优取向的AZO薄膜,其可见光透过率为90%,禁带宽度为3.63 eV,电阻率为1.7×10–3.cm。     

缓冲层对PMS-PNN-PZT压电厚膜材料性能的影响

采用丝网印刷的方法制备了PMS-PNN-PZT四元系压电厚膜陶瓷材料。研究了基板、下电极和PMS-PNN-PZT厚膜层三者之间的高温扩散作用,及SiO2缓冲层对PMS-PNN-PZT压电厚膜的压电性能以及显微结构的影响。用XRD和SEM分析材料的相组成、厚膜定位及压电层的显微结构。结果表明,缓冲层有效地阻止了三者之间的相互扩散,样品的d33、εr等都有所提高,所制得的压电厚膜d33为285pC/N,εr为1210,Qm为1330,kp为0.54。     

TiO2过渡层对Bi3.54Nd0.46Ti3O12薄膜微观结构及电性能的影响

选取厚度为5、10和20nm的TiO2薄膜为过渡层,采用sol-gel法在Pt/Ti/SiO2/Si衬底上制备了Bi3.54Nd0.46Ti3O12(BNT)铁电薄膜,研究了过渡层厚度对铁电薄膜微观结构及电学性质的影响。结果表明,加入TiO2过渡层后,BNT薄膜微观结构得到改善,εr及2Pr值大幅提高,介电损耗及漏电流密度都有降低。过渡层厚度为20nm时,BNT薄膜的εr、tanδ及2Pr值分别为325、0.025(测试频率为10kHz)和36.1×10–6C/cm2,漏电流密度为8.45×10–7A/cm2(外加电场为100×103V/cm)。     

The effect of Mg and Al co-doping on the structural and photoelectric properties of ZnO thin film

Mg–Al co-doped ZnO thin films were prepared via radio-frequency reactive magnetron sputtering technique. X-ray diffraction investigation showed all the thin films with different Mg:Al ratio had hexagonal wurtzite structure. All the thin films showed (100) preferential orientation of ZnO. When Al concentration was kept constant but Mg concentration was increased, the grain size decreased at first and then increased. When Mg:Al ratio was 3:1, the grain size reached a maximum. Ultraviolet–visible spectra showed the thin films had a high average transmittance of 80% in the visible range. The optical band gaps of the thin films were obtained as follows: 3.31, 3.32, and 3.37 eV, corresponding to the Mg:Al ratio of 0:1, 1:1, and 3:1, respectively. Photoluminescence spectroscopy showed all the thin films had four main peaks located at 386, 410, 463, and 499 nm. The origin of blue peak is oxygen vacancy. When Mg concentration was kept constant but Al concentration was increased, I–V curve presented that for both of the heterojunctions the rectifying behavior was formed. The conductivity of Mg:Al=1:1 thin film is higher than that of Mg:Al=1:0 thin film. After illumination, light I–V curve deviated from rectifying character.     

Effect of gate barrier and channel buffer layer on electric properties and transparence of the a-IGZO thin film transistor

Different structures of a-IGZO (amorphous indium gallium zinc oxide) transparent thin film transistor (TTFT) were developed on glass substrate for study of gate barrier and channel buffer layer effects. The used gate barrier and the channel buffer layer are high energy band gap dielectric Al₂O₃ and the rapid thermally annealed ZnO film, respectively. With both gate barrier and channel buffer layers, the TTFT promoted ∼3 orders in on/off current ratio and reduced leakages current ∼800 times. Furthermore, the average transparence was also enhanced from 84% to 86.4% in the range of 500–800 nm wavelengths. The improvement mechanisms are interpreted with comprehensive models in details.     

Strain status in ZnO film on sapphire substrate with a GaN buffer layer grown by metal-source vapor phase epitaxy

ZnO film of 8 μm thickness was grown on a sapphire (0 0 1) substrate with a GaN buffer layer by a novel growth technique called metal-source vapor phase epitaxy (MVPE). The surface of ZnO film measured by scanning electron microscope (SEM) is smooth and shows many regular hexagonal features. The full width at half maximum (FWHM) of ZnO(0 0 2) and (1 0 2) ω-scan rocking curves are 119 and 202 arcsec, corresponding a high crystal quality. The status of the strain in ZnO thick film was particularly analyzed by X-ray diffraction (XRD) ω-2θ scanning. The results show that the strain in ZnO film is compressive, which is also supported by Raman scattering spectroscopy. The compressive strain can solve the cracking problem in the quick growth of ZnO thick film.     

Effects of annealing of MgO buffer layer on structural quality of ZnO layers grown by P-MBE on c-sapphire

We have investigated effects of annealing of MgO buffer layer on structural quality of ZnO layers grown by plasma assisted molecular beam epitaxy on c-sapphire. ZnO layers were characterized by atomic force microscopy, high resolution X-ray diffraction (HRXRD) and cross sectional transmission electron microscopy (TEM). AFM images show that annealing of a low temperature (LT)-MgO buffer at high temperatures enhanced the surface migration of adatoms, leading to the formation of larger terraces and smoother surface morphology, as indicated by the reduction of rms values of roughness from 0.6 to 0.3 nm. HRXRD and TEM experiments reveal that the dislocation density of ZnO layers is reduced from 5.3×10⁹ to 1.9×10⁹ cm⁻² by annealing a LT-MgO buffer. All of those features indicate the structural quality of ZnO layers was improved by annealing a LT-MgO buffer layer.     

ZnO films deposited on GaAs substrates with a SiO2 thin buffer layer

Sputter deposition of ZnO films on GaAs substrates has been investigated. ZnO films were radio frequency (rf)-magnetron sputter deposited on GaAs substrates with or without SiO₂ thin buffer layers. Deposition parameters such as rf power, substrate-target distance, and gas composition/pressure were optimized to obtain highly c-axis oriented and highly resistive films. Deposited films were characterized by x-ray diffraction, scanning electron microscopy (SEM), capacitance, and resistivity measurements. Thermal stability of sputter-deposited ZnO films (0.5–2.0 μm thick) was tested with a post-deposition heat treatment at 430°C for 10 min, which is similar to a standard ohmic contact alloying condition for GaAs. The ZnO/SiO₂/GaAs films tolerated the heat treatment well while the ZnO/GaAs films disintegrated. The resistivity (10¹¹ Ω-cm) of the ZnO films on SiO₂-buffered GaAs substrates remained high during the heat treatment. The post-deposition anneal treatment also enhances c-axis orientation of the ZnO films dramatically and relieves intrinsic stress almost completely. These improvements are attributed to a reduction of grain boundaries and voids with the anneal treatment as supported by SEM and x-ray diffraction measurement results.     

ZnO和Al2O3缓冲层对AZO透明导电膜薄膜性能的影响

采用射频磁控溅射法,以纯度为99.9%,质量分数98%ZnO、2%Al2O3陶瓷靶为溅射靶材,在预先沉积了ZnO和Al2O3的玻璃衬底上制备了Al2O3掺杂的ZnO薄膜。研究并对比了两种不同的缓冲层对ZnO∶Al(AZO)薄膜的微观结构和光电性能的影响。并借助X线衍射(XRD)仪、扫描电子显微镜(SEM)、紫外可见光谱仪(UV-Vis)等方法测试和分析了不同缓冲层,对AZO薄膜的形貌结构、光电学性能的影响。结果表明:加入缓冲层后,在衬底温度为200℃时,溅射30min,负偏压为60V、在氮气气氛下经300℃退火处理后,制得薄膜的可见光透过率为83%～87%,AZO薄膜的最低电阻率,从9.2×10-4Ω.cm(玻璃)分别下降到8.0×10-4Ω.cm(ZnO)和5.4×10-4Ω.cm(Al2O3)。     

Atomic layer deposition of ZnO on graphene for thin film transistor

A ZnO/graphene composite thin film was obtained by depositing ZnO on graphene through an Atomic Layer Deposition (ALD) process. The graphene layer was synthesized through a Chemical Vapor Deposition (CVD) process. The achievement of ZnO deposition on graphene was attributed to the Perylene Tetracarboxylic Acid (PTCA) treatment on graphene. Both ZnO Thin Film Transistor (TFT) and ZnO/graphene TFT were fabricated and tested. The results show that both of them displayed a high ON/OFF ratio, while ZnO/graphene TFT displayed an enhanced carrier mobility over ZnO TFT.     

生长ZnO薄膜的氧分压对ZnO/PS体系光学性能的影响

采用电化学阳极氧化法,在p型（100）晶向的单晶Si片上制备多孔Si（PS）样品;以PS为衬底,采用射频反应磁控溅射技术在不同O2分压下沉积ZnO薄膜。X射线衍射（XRD）结果显示,所有ZnO/PS复合体系在衍射角为34.24°附近均出现较强的衍射峰,对应于ZnO的（002）晶面,说明样品具有良好的c轴择优取向;但由于...     

氩氧分压比对ZnO薄膜的结构及电学性能的影响

采用射频磁控溅射法制备了氧化锌基薄膜晶体管(ZnO-TFTS),研究了氩氧分压比对ZnO薄膜生长以及ZnO-TFT电学特性的影响。结果表明:氩氧分压比为40/16和40/8时制得的ZnO-TFT样品,都存在氧过量现象,生长晶向都存在一定左偏移,有源层沟道都为n型,均工作在增强型模式下,饱和特性都较好,且都呈现出一个较大的负方向漏电流,但氩氧分压比为40/16时制备的ZnO薄膜结晶性更好,其所对应的ZnO-TFT具有更高的场效应迁移率和开关电流比,以及更低的亚阈值摆幅。