激光作用下GeS2非晶半导体薄膜的性能及结构变化

采用514.5nm波长的氩离子激光器，结合X射线衍射分析（XRD）、红外光谱分析（IR）、扫描电镜分析（SEM）和透射光谱分析，研究了GeS2非晶半导体薄膜在激光辐照后的性能及结构变化。实验结果发现，经热处理和激光辐照后，薄膜的光学吸收边均移向短波长处，并且随着辐照激光强度和辐照时间的增加而增加，这种平移在退火薄膜中是可逆的。SEM结果分析表明，薄膜在激光辐照后有晶相出现，且随着辐照激光强度的增加，晶相更多。     

ZnO纳米晶薄膜的制备及特性分析

在低温下制备了粒径小于10nm的ZnO纳米晶,用旋涂法制备ZnO纳米晶薄膜,XRD分析ZnO晶相是纤锌矿结构;SEM与AFM表明,纳米晶薄膜在300％退火后薄膜的厚度明显减小到130nm,表面粗糙度降低到3．27nm,粒径明显增大;紫外-可见吸收和透射比光谱表明,随着退火温度的增加,吸收边发生了红移,吸收肩更明显,薄膜具有高的透射率（75—85％）;薄膜方阻随温度增加而增大,300℃以下退火方阻增加很小（小于8．5Ω／sq）,400℃以上退火方阻大幅增加（大于21．1Ω／sq）,因此,ZnO纳米晶薄膜最优退火温度点为300℃。     

立方相Y掺杂ZrO2纳米晶薄膜的制备与辐照效应研究

采用溶胶-凝胶结合旋涂法在单晶Si衬底上制备了立方相Y掺杂ZrO₂纳米晶薄膜(YSZ), 并分析了制备工艺参数对YSZ成膜的影响。采用光学显微镜、扫描电子显微镜、X射线衍射和透射电镜等手段对样品进行了表征和分析。结果表明, 加入PVA作为分散剂、采用分级干燥工艺以及提高匀胶转速可大大提高YSZ薄膜的成膜质量, 制备的YSZ薄膜表面十分平整, 没有出现裂纹。YSZ薄膜为立方相结构, 没有出现其它相。薄膜由平均晶粒尺寸为9.4 nm的纳米晶组成, 薄膜的厚度约为60 nm。在室温条件下, 低剂量的Xe离子辐照YSZ薄膜后出现微裂纹, 而当辐照剂量比较高时, 由于热峰效应, 辐照引起的微裂纹逐渐发生愈合。并且, 随着辐照剂量的增加, YSZ薄膜的平均晶粒尺寸增大。     

铝诱导非晶硅薄膜快速低温晶化研究

采用金属铝诱导晶化非晶硅薄膜的方法制备多晶硅薄膜。研究了不同的退火温度对a-Si薄膜晶化的影响，采用XRD，Raman，SEM等测试手段分析了实验结果。实验结果发现非晶硅薄膜在400℃下退火20min薄膜仍为非晶结构（a-Si），在450℃下退火20min后非晶硅开始晶化且随着温度的升高，且晶化程度加强。     

低温水浴制备ZnO纳米晶薄膜的研究

首先在低温下制备了粒径小于10nm的ZnO纳米晶,然后采用旋口法制备了ZnO纳米晶薄膜,XRD分析ZnO晶相是纤锌矿结构;SEN与AFM表明,纳米晶薄膜在300℃退火后薄膜的厚度明显地减小到130nm（未退火200nm）,粒径明显增大,表面粗糙度减少到3．27nm（未退火4．89nm）;紫外-可见吸收和透射比光谱表明,随着退火温度的增加,吸收边发生了红移,吸收肩更明显,薄膜具有高的透射率（75—85％）,随着温度增加薄膜方阻增大,300℃以下退火方阻增加很小（小于8．5Ω／sq）,400℃以上退火方阻大幅增加（大于21．1n／sq）,假定存在最优退火温度点（300℃）。     

纳米TiO2薄膜光催化剂的制备及性能研究

以钛酸四丁酯作为前驱体,用溶胶一凝胶法,在玻璃载体上煅烧制备了纳米TiO2薄膜光催化剂,利用扫描电子显微镜（SEM）、X射线衍射（XRD）等表征技术研究了TiO2薄膜的形貌和特性,其光催化性能用4支20W紫外石英杀菌灯照射TiO2薄膜分解亚甲基兰染料溶液表征,结果表明,该催化剂具有锐钛班红石混合晶相和纳米花状结构,纳米TiO2薄膜的光催化能力随着镀膜层数的增加而增加。     

基于增透膜的非晶硅薄膜激光低损伤晶化工艺研究

研究了一种非晶硅薄膜的激光低损伤晶化工艺方法,通过在非晶硅薄膜上淀积氮化硅薄膜方法研究激光退火改善非晶硅薄膜的质量。实验结果表明,随着激光退火频率的增加,有无增透膜样品的衍射强度均会出现先下降后上升再下降的现象。增透膜样品的最强衍射峰出现在10~15Hz激光退火后,而无增透膜样品的最强衍射峰则出现在20Hz激光退火后。SEM分析表明,应用增透膜可以降低非晶硅薄膜的激光退火脉冲频率,并减少非晶硅薄膜激光损伤,可作为一种低损伤的激光晶化工艺。     

无机盐-螯合-凝胶法制备的铁酸铋薄膜的工艺研究

采用无机盐-螯合-溶胶凝胶法成功制备了BiFeO3薄膜.研究了不同基片、热处理工艺对薄膜相结构的影响.通过DTA-TG与FT IR对溶胶前躯体进行表征,分析了BiFeO3溶胶与薄膜过程机理并确定了铁电相转变温度为856℃.通过XRD、SEM分析了薄膜的晶相及表面形貌.结果表明,薄膜呈随机取向,氮气环境中退火可提高薄膜结晶度.600℃退火下薄膜厚度平均是400nm左右.VSM表明随着退火温度的增加,BiFeO3薄膜的磁化率增大.     

硅基氧化铱薄膜的脉冲激光沉积及其微观结构研究

采用脉冲激光沉积技术，在Si（100）基片上制备了高致密的氧化铱（IrO2）薄膜，研究了不同沉积温度对薄膜结构的影响。利用X射线衍射（XRD）、拉曼光谱、扫描电镜（SEM）和原子力显微镜（AFM）对制备的IrO2薄膜进行了表征。结果表明：在20Pa氧分压，250℃～500℃范围内，得到的薄膜为多晶的IrO2物相，其晶粒尺寸和粗糙度随着沉积温度的升高而增加；所得到的IrO2薄膜表面粗糙度低，厚度均匀，与基片结合良好。     

真空共蒸发法制备CuxTe薄膜的结构特性分析

用真空共蒸发法制备了CuxTe（1≤x≤2）薄膜,并通过X射线衍射（XRD）、X射线光电子能谱（XPS）及原子力显微镜（AFM）等表征手段分析了薄膜的结构特性,研究了热处理对不同Cu/Te配比的样品物相转变的影响。结果发现：刚沉积的薄膜非晶结构占主导地位,只有部分低Cu/Te比的薄膜出现多晶结构;退火后,薄膜发生晶相转变,且随着退火温度的升高,不同配比的样品有着不同程度的物相转变。其中,较低配比（x=11、.44）的样品多晶转变较为明显,结晶度较高,说明较小x值的薄膜晶化温度较低,而高x值的薄膜晶化温度较高。用CuxTe薄膜作为背接触层,获得了效率为12.5%的CdS/CdTe小面积太阳电池。     

硫系Ge-As-S玻璃和薄膜的特性

用差热分析，X射线衍射分析和透射光谱分析等手段研究了硫系Ge-As-S玻璃和薄膜的性能，结果表明，Ce-As-S体系的成玻能力较强在空气中自然冷却就能成玻，其（Tg-Tc)/Tg值为0.127-0.289，经激光辐射后的Ge-As-S玻璃薄膜的透射光谱曲线向短波方向移动，且平移的大小随激光功率的增加而增加，薄膜的透射光谱线的平移表明激光辐射导致薄膜光致结构变化，利用电子束辐射极化，通过Maker条纹测试方法在Ge-As-S玻璃中观察到二次谐波。     

Photoelectrical Response in Single‐Layer Graphene Transistors

The illumination of single‐layer graphene (SLG) transistors with visible light causes a negative shift in their transfer curves, attributable to the desorption of oxygen. However, their hysteresis is not affected by illumination, which suggests that charge traps are not affected by the visible‐light exposure. When SLG transistors are covered with a layer of photoactive polymer, the photodesorption‐induced current change in the transistors becomes less significant than the effects caused by the surrounding photoactive polymer. These observations demonstrate that the photoelectrical response of SLG transistors is dominated by extrinsic mechanisms rather than by the direct photocurrent process. The results suggest a new strategy for achieving light detection. The large cross section of SLG films for receiving photons and the capability of tailoring photoelectrical properties on them is potentially useful for optoelectronic applications.     

Light illumination effects in ambipolar FETs based on poly(3-hexylthiophene) and fullerene derivative composite films

The effects of light illumination on field effect transistors based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C₆₁-butyric methyl ester (PCBM) composite films have been studied. It is found that the light illumination on pure P3HT and PCBM generally resulted in decrease of the threshold voltages and increase of the mobilities by a little. In the composite film at the PCBM contents of x = [P3HT] / ([P3HT] + [PCBM]) = 0.67 ∼ 0.9, an ambipolar field transport appeared. The light illumination effect was observed remarkably in the shift of threshold voltage for the hole generation at x = 0.75. Variations of Hole and electron mobilities and threshold voltage of electron generation upon light illumination were basically similar to those of the pure materials. The results were discussed in terms of the light assisted carrier generation in field effects.     

Sintering effect on the optoelectronic characteristics of HgSe nanoparticle films on plastic substrates

The optoelectronic characteristics of HgSe nanoparticle films spin-coated on flexible plastic substrates are investigated under the illumination of 1.3 μm wavelength light. The sintering process improves the optoelectronic characteristics of the HgSe nanoparticle films. The photocurrent of the sintered HgSe nanoparticle films under the illumination of 1.3 μm wavelength light is approximately 20 times larger in magnitude than that of the non-sintered films in air at room temperature. Moreover, the endurance of the flexible optoelectronic device investigated by the continuous substrate bending test reveals that the photocurrent efficiency changes negligibly up to 250 cycles.     

New azobenzene polymers for light-controlled optical elements

Three new azobenzene polymers have been synthesized by polymerization of cyanazobenzene monomers with different numbers of methylene groups attached to the cyanazobenzene dye. The rearrangement of the anisotropic azobenzene moieties in them was initiated by illumination with linearly polarized light (488 nm), and the optical anisotropy due to this arrangement has been investigated. The photobirefringence can be erased by illumination with circularly polarized light and re-induced to the same value with linearly polarized light. We show that films from these polymers can be used as optically controlled reversible polarization elements.     

Broadband photovoltaic effect of n-type topological insulator Bi<Subscript>2</Subscript>Te<Subscript>3</Subscript> films on p-type Si substrates

We report the photovoltaic effects of n-type topological insulator (TI) Bi2Te3 films grown on p-type Si substrates by chemical vapor deposition (CVD).The films containing large nanoplates with a smooth surface formed on p-Si exhibit good p-n diode characteristics under dark and light illumination conditions and display a good photovoltaic effect under the broadband range from ultraviolet (UV) to near infrared (NIR) wavelengths.Under the light illumination with a wavelength of 1,000 nm,a short circuit current (Isc) of 19.2 μA and an open circuit voltage (Voc) of 235 mV are achieved.The maximum fill factor (FF) increases with a decrease in the wavelength or light density,achieving a value of 35.6％ under 600 nm illumination.The photoresponse of the n-Bi2Te3/p-Si device can be effectively switched between the on and off modes in millisecond time scale.These findings are important for both the fundamental understanding and solar cell device applications of TI materials.     

WO3+掺杂对纳米TiO2薄膜可见光致亲水性的影响

用溶胶-凝胶法和浸渍-提拉工艺在载波片上制备了均匀、透明的WO^3＋掺杂的纳米TiO2薄膜.用XRD、紫外-可见分光光度计分析了样品的晶相和光吸收性能,研究了WO^3＋的掺杂、掺杂量及热处理温度对薄膜可见光致亲水性的影响,并考察了薄膜在停止光照后,其亲水性能的变化.结果表明,与纯TiO2薄膜相比,掺WO^3＋的TiO2薄膜对可见光的吸收有所增强,并有一定的红移现象,且在可见光照射下,亲水性能都有提高,WO^3＋的最佳掺杂量为3%（物质的量比）;薄膜的最佳煅烧温度为773K;停止光照后,掺WO3＋的TiO2薄膜亲水性能持续的更久.     

Photoinduced hydrophilicity of titanium dioxide thin films prepared by cathodic electrodeposition

Crystal structure and microstructural properties of titanium dioxide thin films prepared by cathodic electrodeposition on indium-tin-oxide coated glass substrates from aqueous peroxo-titanium complex solutions have been investigated as a function of sintering temperature (25-500 °C) for the first time. We have noticed pronounced photoinduced hydrophilicity for such thin films on exposure to ultraviolet (UV) light illumination. It was observed that all the films, irrespective of their crystalline nature (amorphous and crystalline), display transformation from hydrophobic to super-hydrophilic behavior upon UV illumination. This observation can be correlated with typical nanoporous morphology of electrodeposited TiO₂ films.     

Non-equilibrium carrier relaxation in sprayed CdSe films

The rise and decay of the photocurrent in CdSe films prepared by spray pyrolysis were investigated. The decay time at an illumination of 10 mW cm^?2 was 1.6 ms. The dependence of the decay time on the light intensity, the background illumination and the chopping frequency was examined. The lifetime of the majority carriers, as deduced from the decay curve, was found to vary with the illumination, which gives a clue to the superlinearity shown in the illumination-current characteristics of these films. At 5 mW cm^?2 the lifetime was 0.8 ms and at 10 mW cm^?2 it was 1.6 ms. The amplitude of photoconductivity decrased by 33% when the frequency of the chopper was increased from 50 to 270 Hz.