染料敏化太阳能电池TiO2薄膜电极的染料吸附性能研究

采用手工刮涂法制备了染料敏化太阳能电池( DSSC)的TiO2薄膜电极,用解吸的方法和正交试验研究了DSSC电池TiO2薄膜电极的染料吸附性能,并结合统计分析方法对染料吸附试验数据进行了分析处理.研究结果表明TiO2薄膜电极具有最优染料吸附性能的烧结条件为:以2℃/min的速率升温至450℃,保温50 min后随炉冷却...     

TiO_2纳米管阵列对染料敏化太阳能电池性能的影响

通过恒压阳极氧化法在Ti箔表面制备了结构规整的TiO2纳米管阵列,研究了氧化时间和退火温度对纳米管阵列的尺寸和晶体结构的影响。用制得的纳米管阵列电极组装了染料敏化太阳能电池(DSSC),研究了纳米管长度、退火温度和电极面积对DSSC光电性能的影响。结果表明,纳米管管径和壁厚均与氧化时间无关,而纳米管长度则随着氧化时间延长而增加。在450℃及更低温度退火时,纳米管中只出现锐钛矿相;而在500℃退火时,纳米管中则又出现了金红石相。由厚度为27μm、退火温度为450℃的纳米管阵列电极组装成的DSCC具有最佳的光电转化性能。DSCC的光电转化效率随电极面积的增加而降低。     

低温制备柔性染料敏化太阳电池TiO2薄膜电极

采用丝网印刷技术在柔性基底ITO/PET上制备TiO2多孔薄膜,经过低温烧结得到TiO2多孔薄膜电极。以D102染料为敏化剂,KI/I2为电解质,Pt电极为对电极,制成电池后测试了电池的光电性能。结果表明:以乙醇作为分散剂添加到P25粉体中,采用丝网印刷技术制膜,100℃低温烧结可以在柔性基底ITO/PET上制备出表面粗糙度良好、具有一定光电性能的TiO2多孔薄膜电极,用其制作的太阳电池转换效率达1.33%。     

退火工艺对钛酸锶钡薄膜结构的影响

采用射频磁控溅射在Pt/Ti/SiO2/Si(100)衬底上制备Ba0.6Sr0.4TiO3(BST)铁电薄膜,在500~750℃之间对薄膜快速退火。XRD分析表明:500℃时BST薄膜开始晶化为ABO3型钙钛矿结构,温度越高结晶越完整,晶粒越大。理论计算表明,薄膜在低温退火后无择优取向,高温退火后在(111)、(210)晶面有择优取向。退火气氛、保温时间、循环次数等因素对薄膜晶粒大小无明显影响,但对表面粗糙度和结晶程度影响较大。     

后处理工艺对PCT薄膜形貌与结构的影响

采用射频磁控溅射技术,利用快速退火工艺制备出了大面积(φ120 mm)表面光滑、连续、均匀的(Pb,Ca)TiO3(PCT)薄膜。原子力显微镜和X射线衍射分析结果表明,快速退火处理工艺较常规退火处理工艺具有晶化温度低、晶化时间短、薄膜结晶性能好、易与微电子工艺兼容等优点。经500～550快速退火处理后,PCT薄膜已完全形成钙钛矿结构,最佳晶化温度约为550。     

sol-gel法制备纳米TiO_2-SiO_2宽带高增透膜

通过模拟计算设计出一种透射比为99%、包含一层TiO2薄膜和一层SiO2薄膜的宽带高增透膜。两层薄膜均由溶胶-凝胶法制得并采用提拉法成形于玻璃基片上。对增透膜样品的透射比、表面形貌、膜厚等进行了表征,考察了提拉速度、退火温度、催化条件等对其透射比、表面均匀性的影响。结果表明:增透膜的使用提高了玻璃基片的透射比;当提拉速度为9cm/min,增透膜厚约为255nm时,基片在400～800nm波段的透射比提高了7%。控制退火温度,可以使增透膜在某些波段的透射比增强。增透膜样品的表面均匀性良好,室温下膜层的均方根表面粗糙度(RMS)为1.682,平均粗糙度(RA)为1.208,在550℃的温度以下,随着退火温度升高,表面粗糙度降低。     

WO3 passivation layer-coated nanostructured TiO2: An efficient defect engineered photoelectrode for dye sensitized solar cell

Major loss factors for photo-generated electrons due to the presence of surface defects in titanium dioxide (TiO2) were controlled by RF-sputtered tungsten trioxide (WO3) passivation.X-ray photoelectron spectroscopy assured the coating of WO3 on the TiO2 nanoparticle layer by showing Ti 2p,W 4f and O 1 s characteristic peaks and were further confirmed by X-ray diffraction studies.The coating of WO3 on the TiO2 nanoparticle layer did not affect dye adsorption significantly.Dye sensitized solar cells (DSSCs) fabricated using WO3-coated TiO2 showed an enhancement of ～10％ compared to DSSCs fabricated using pristine TiO2-based photo-electrodes.It is attributed to the WO3 passivation on TiO2 that creates an energy barrier which favored photo-electron injection by tunneling but blocked reverse electron recombination pathways towards holes available in highest occupied molecular orbital of the dye molecules.It was further evidenced that there is an optimum thickness (duration of coating) of WO3 to improve the DSSC performance and longer duration of WO3 suppressed photo-electron injection from dye to TiO2 as inferred from the detrimental effect in short circuit current density values.RF-sputtering yields pinhole-free,highly uniform and conformal coating of WO3 onto any area of interest,which can be considered for an effective surface passivation for nanostructured photovoltaic devices.     

影响Al-Ti复合氧化膜比容的工艺因素研究

用水解沉积-阳极氧化法制备高介电常数的Al-Ti复合氧化膜,研究了含钛无机盐溶液的浓度、温度、pH值处理时间,以及退火温度对Al-Ti复合氧化膜比容增长率的影响。结果表明,铝腐蚀箔在浓度为0.002mol/L、pH1.5的含钛无机盐溶液中,65℃浸渍处理10min,取出并烘干后的样品,550℃热处理10min,所制得的Al-Ti复合氧化膜比容最大。35V阳极氧化电压下,比容提高率大于30%。     

退火温度对纳米TiO2薄膜微结构的影响

利用XRD、IR、UV-VIS、AFM、XPS等手段,研究了退火温度对溶胶–凝胶法制备的纳米TiO2薄膜微结构和表面形貌的影响。450~600℃退火处理的薄膜呈锐钛矿和金红石型混晶结构,700℃退火后为纯金红石相;水峰的吸收峰消失在300~500℃之间,至500℃有机基团完全消失,薄膜表面主要有C,Ti,O三种元素;改变退火温度,可以使薄膜的禁带宽度在3.26~3.58eV之间变化,可以在一定范围内,获得不同折射率的TiO2纳米薄膜;薄膜的表面粗糙度(RMS)为2~3nm。     

Evolution of ZnO architecture on a nanoporous TiO2 film by a hydrothermal method and the photoelectrochemical performance

The synthesis of ZnO architecture on a fluorine-doped SnO2 (FTO) conducting glass pre-coated with nanoporous TiO2 film has been achieved by a one-step hydrothermal method at a temperature of 70 ℃.The effect of the reaction time on the morphology of the ZnO architecture has been investigated,and a possible growth mechanism for the formation of the ZnO architecture is discussed in detail.The morphology and phase structures of the as-obtained composite films have been investigated by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD).The results show that the growth time greatly affects the morphology of the obtained ZnO architecture.The photoelectrochemical performances of as-prepared composite films are measured by assembling them into dye sensitized solar cells (DSSCs).The DSSC based on the as-prepared composite film (2 h) has obtained the best power conversion efficiency of 1.845％.     

Enhanced electron injection/transportation by surface states increment in mesoporous TiO2 dye-sensitized solar cells

A strategy of surface modification to the mesoporous TiO2 photoanode with hydrochloric acid treatment was used in this study, and it was found that short circuit current and photovoltaic efficiency of dyesensitized solar cells (DSSCs) were increased by 5.5% and 8.9% respectively. The improvement was attributed to the reduced impedances in the TiO2 film and at the TiO2/dye/electrolyte interface. It was showed that the increased surface electronic states could remarkably prolong electron lifetime, which was responsible for the reduction of impedances. Under these quasi-continuous states in mesoporous structure, the electron injection/transportation can be notably facilitated, which will be beneficial for the DSSC performance.     

退火温度对WO_3薄膜结构及气敏性能的影响

采用直流磁控溅射法制备了WO3薄膜,并在350~550℃时对薄膜进行退火处理,研究了退火温度对薄膜结构及气敏性能的影响。结果表明:退火前及350℃退火后的薄膜为非晶态,450℃和550℃退火后的薄膜为WO3–x型晶态;随退火温度的提高,薄膜厚度增加,晶粒度增大。550℃退火后薄膜的厚度,较450℃退火后薄膜厚30nm,晶粒度相差8nm;450℃和550℃退火后的薄膜,在150℃时对体积分数为0.05%的NO2的灵敏度接近于22。     

Role of thermal annealing on SiGe thin films fabricated by PECVD

Amorphous Silicon Germanium (a-SiGe) thin films of 500 nm thickness are deposited on silicon substrates using Plasma Enhanced Chemical Vapour Deposition (PECVD). To obtain polycrystalline nature of films, thermal annealing is done at various temperature (450–600 °C) and time (1–10 h). The surface morphology of the pre- and post-annealed films is investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The crystallographic structure of the film is obtained by X-ray diffraction method. Raman spectroscopy is carried out to quantify the Ge concentration and the degree of strain relaxation in the film. Nano-indentation is performed to obtain the mechanical properties of the film. It is found that annealing reduces the surface roughness of the film and increases the Ge concentration in the film. The grain size of the film increases with increase in annealing temperature. The grain size is found to decrease with increase in annealing time up to 5 h and then increased. The results show that 550 °C for 5 h is the critical annealing condition for variation of structural and mechanical properties of the film. Recrystallization starts at this condition and results in finer grains. An increase in hardness value of 7–8 GPa has been observed. Grain growth occurs above this critical annealing condition and degrades the mechanical properties of the film. The strain in the film is only relaxed to about 55% even for 10 h of annealing at 600 °C. Transmission Electron Microscopy (TEM) observations show that the strain relaxation occurs by forming misfit dislocations and these dislocations are confined to the SiGe/Si interface.     

PECVD制备纳米晶多晶硅薄膜

以Si(100)为衬底,采用磁控溅射和射频等离子体增强化学气相沉积系统制备了Si(100)/Al膜/非晶Si膜结构的样品。对该样品进行Al诱导真空退火以制备多晶硅薄膜,采用X射线衍射仪(XRD)和AFM分析薄膜微结构及表面形貌。实验结果表明,在经过500℃、550℃Al诱导退火后,形成了择优取向为〈111〉晶向的多晶硅薄膜。AFM给出了550℃退火后薄膜表面形貌,为100～200nm大小的圆丘状硅晶粒,密集排列在薄膜表面;并对Al诱导真空退火晶化的机理进行了分析。     

PLD法制备ZnO薄膜的退火特性和蓝光机制研究

通过脉冲激光沉积(PLD)方法,在O2中和100～500℃衬底温度下,用粉末靶在Si(111)衬底上制备了ZnO薄膜,在300℃温度下生长的薄膜在400～800℃温度和N2氛围中进行了退火处理,用X射线衍射(XRD)谱、原子力显微镜(AFM)和光致发光(PL)谱表征薄膜的结构和光学特性。XRD谱显示,在生长温度300℃时获得较好的复晶薄膜,在退火温度700℃时获得最好的六方结构的结晶薄膜;AFM显示,在此退火条件下,薄膜表面平整、晶粒均匀;PL谱结果显示,在700℃退火时有最好的光学特性。     

SiO2/4H-SiC界面氮化退火

通过1 300℃高温干氧热氧化法在n型4H-SiC外延片上生长了厚度为60 nm的SiO2栅氧化层.为了开发适合于生长低界面态密度和高沟道载流子迁移率的SiC MOSFET器件产品的栅极氧化层退火条件,研究了不同退火条件下的SiO2/SiC界面电学特性参数.制作了MOS电容和横向MOSFET器件,通过表征SiO2栅氧化层C-V特性和MOSFET器件I-V特性,提取平带电压、C-V磁滞电压、SiO2/SiC界面态密度和载流子沟道迁移率等电学参数.实验结果表明,干氧氧化形成SiO2栅氧化层后,在1 300℃通入N2退火30 min,随后在相同温度下进行NO退火120 min,为最佳栅极氧化层退火条件,此时,SiO2/SiC界面态密度能够降低至2.07×1012 cm-2·eV-1@0.2 eV,SiC MOSFET沟道载流子迁移率达到17 cm2·V-1·s-1.     

染料敏化TiO_2单晶纳米棒阵列太阳电池的性能

采用水热法一步合成出TiO2单晶纳米棒有序阵列,进而制备出染料敏化太阳电池。重点探讨了退火时间变化对电池光电转化效率的影响。研究结果表明,与未退火的纳米棒组装而成的电池相比,退火后的纳米棒电池显示出更高的光电转化效率。并且当退火时间为7 min时,光电转化效率最高(5.05%),提高到未退火电池光电转化效率的300%以上。电池性能提高的原因有:TiO2纳米棒阵列与衬底间结合力的增强有利于电子传输;表面态缺陷的减少有利于抑制光生载流子的复合。结合SEM,TEM和J-V曲线等表征手段探讨了这一现象背后的物理机制。     

Schottky barrier parameters and structural properties of rapidly annealed Zr Schottky electrode on p-type GaN

The Schottky barrier junction parameters and structural properties of Zr/p-GaN Schottky diode are explored at various annealing temperatures. Experimental analysis showed that the barrier height (BH) of the Zr/pGaN Schottky diode increases with annealing at 400℃ (0.92 eV (I-V)/1.09 eV (C-V)compared to the asdeposited one (0.83 eV (I-V)/0.93 eV (C-V). However, the BH decreases after annealing at 500℃. Also, at different annealing temperatures, the series resistance and BH are assessed by Cheung''s functions and their values compared. Further, the interface state density (N_SS)of the diode decreases after annealing at 400℃ and then somewhat rises upon annealing at 500℃. Analysis reveals that the maximum BH is obtained at 400℃, and thus the optimum annealing temperature is 400℃ for the diode. The XPS and XRD analysis revealed that the increase in BH may be attributed to the creation of Zr-N phases with increasing annealing up to 400℃. The BH reduces for the diode annealed at 500℃, which may be due to the formation of Ga-Zr phases at the junction. The AFM measurements reveal that the overall surface roughness of the Zr film is quite smooth during rapid annealing process.     

非晶硅薄膜的镍诱导横向晶化工艺及其特性

报道了镍诱导非晶硅薄膜的晶化技术,探讨了镍诱导晶化机理．详细调查了诱导晶化时间和温度对晶化速率的影响,并用Raman、AFM和TEM等测试了材料的特性．实验结果发现用该方法可以获得较大晶粒的多晶;在晶化温度为625℃左右时晶体横向晶化速率最高．如要获得较长的晶体,低温退火则比较有利．     

ULSI Cu互连CoSiN扩散阻挡薄膜的研究

CoSiN薄膜可以作为超大规模集成电路Cu布线互连材料使用。利用磁控溅射技术制备了CoSiN/Cu/CoSiN/SiO2/Si薄膜,利用四探针测试仪、薄膜测厚仪、原子力显微镜、X射线光电子能谱仪等来检测多层膜电阻率、薄膜厚度、表面形貌、元素含量及价态等。考察亚45 nm级工艺条件下CoSiN薄膜对Cu的扩散阻挡性能。实验结果表明,在氩气气氛条件下经500℃,30 min热退火处理后多层膜的电阻率和成分没有发生明显变化,CoSiN薄膜能够保持良好的铜扩散阻挡性能;经600℃,30 min热退火处理后,Cu大量出现在表面,CoSiN薄膜对Cu失去扩散阻挡性能。