H2S气氛下硫化温度对Cu2ZnSnS4薄膜性能影响的研究

用磁控溅射法在玻璃衬底上沉积Zn/Sn/Cu预置层,然后再在H2S气氛下将其硫化制成Cu2ZnSnS4(CZTS)薄膜。研究了不同硫化温度(460,500,540和580℃)对CZTS薄膜性能的影响。采用X射线衍射、Raman、扫描电镜、能量色散谱和紫外-可见-近红外分光光度计表征薄膜的物相、表面形貌和光学性能。结果表明,在不同硫化温度下都成功制备了CZTS薄膜。当硫化温度为540℃时,制备的薄膜晶粒达到2μm,结晶性最好,表面致密光滑,而且它的吸收系数大于7×104cm-1,禁带宽度为1.49 e V。硫化温度较低(460℃)时,含有Cu2-xS杂质相,表面存在孔洞。而硫化温度较高(580℃)时,晶界处会产生微裂纹。     

氧离子能量对离子束辅助沉积Al2O3薄膜的结构及光学性能的影响

利用氧离子束辅助脉冲反应磁控溅射技术在聚酰亚胺基底上沉积Al2O3薄膜。这项技术在溅射高纯铝靶材的同时利用低能氧离子进行氧化来控制薄膜的化学配比。研究了薄膜沉积过程中离子束辅助的作用以及离子束放电电压对Al2O3薄膜的化学成分、结构、表面形貌、光学性能以及沉积速率的影响。结果发现,离子束放电电压对薄膜的化学成分具有显著影响,当电压增加到200 V,薄膜已基本达到完全化学计量比且薄膜为非晶结构;薄膜表面粗糙度随着离子束放电电压的增加而减小,当电压达到300V时,薄膜具有最小的表面粗糙度;通过对Al2O3薄膜透射谱的测量,分析薄膜的光学特性,获得了薄膜的光学常数随离子束放电电压的变化规律,发现氧离子束辅助沉积的薄膜具有较高的折射系数和较低的消光系数;另外,薄膜的沉积速率在电压增加到300V时达到最大值70 nm/min,是未采用离子束辅助时沉积速率的5倍。     

磁控溅射制备Cu2ZnSnS4薄膜的研究进展

Cu_2ZnSnS_4(CZTS)薄膜由于其合适的禁带宽度、高的光吸收系数以及组分无毒、储量丰富等特性,被视为薄膜太阳能电池最佳的吸收层材料之一。磁控溅射是制备CZTS薄膜的主要方法之一,因为其制备过程相对简单且可以产业化,一直是太阳能电池领域的研究热点。从磁控溅射制备CZTS薄膜的3种路径出发,综述了近年来各种路径在制备CZTS薄膜方面的研究进展,比较了3种路径的优缺点,同时对磁控溅射制备CZTS薄膜的发展前景进行了展望。     

Cu2ZnSnS4薄膜光电性能及其太阳电池的制备和研究

采用硫化Zn/Sn/Cu金属多层膜的方法制备了太阳电池吸收层用的Cu2ZnSnS4(CZTS)薄膜。用X射线衍射仪、拉曼光谱仪、紫外-可见近红外分光光度计、扫描电镜、能谱仪及数字源表等对薄膜进行了一系列的表征。结果表明制备的CZTS薄膜没有杂相存在并具有标准拉曼峰。薄膜在可见光范围内的吸收系数>104cm-1,同时其光学带隙接近1.5eV。CZTS薄膜具有均匀致密的表面形貌,薄膜元素比例非常接近标准化学计量比。此外,CZTS薄膜呈现显著的光电流响应性能,其光电流的激发和衰减时间分别为0.0736和0.2646s。     

表面活性剂PVP、CTAB协同效应对制备Cu2ZnSnS4微粒的影响

采用溶剂热法,以CuCl2·2H2O、Zn(Ac)2·2H2O、SnCl4·5H2O作金属源,硫脲作硫源,乙二醇作溶剂,在体系中加入不同表面活性剂PVP和CTAB,研究PVP、CTAB协同效应对制备CZTS颗粒的影响。通过XRD、SEM、UV-Vis方法检测分析CZTS颗粒的物相、结构、形貌以及光学性能。结果表明:所得CZTS颗粒均具有锌黄锡矿结构;当在体系中同时加入PVP、CTAB时,两者的协同效应使得颗粒形貌发生明显变化,光学带隙也发生相应变化;当体系中加入的表面活性剂PVP∶CTAB=3∶1时,合成的颗粒结晶性较好、颗粒形貌为单分散似花状微粒、光学带隙为1.48 eV,与太阳能电池所需的最佳带隙接近。最后,提出了相应的机理。     

Zn掺杂Sn2S3薄膜的特性

高纯Sn和S粉按1∶0.41%(质量分数)配比,均匀掺入9%(质量分数)的高纯Zn粉,单源共蒸发沉积薄膜后再进行热处理,得到Sn2S3∶Zn薄膜。XRD分析显示,380℃,55min热处理得到简单正交晶系的纯Sn2S3薄膜。掺Zn 9%(质量分数)的薄膜经370℃热处理15min得到的薄膜仍属简单正交晶系。掺Zn后Sn2S3薄膜的表面均匀和致密性变好,平均晶粒尺寸从未掺Zn时的35.69nm增加到58.80nm。Sn2S3薄膜的导电类型均为N型,掺Zn后薄膜的电阻率为60.5(Ω·cm),比未掺杂时降低1个数量级。Sn2S3薄膜的直接光学带隙为1.85eV,本征吸收边为551nm;Sn2S3∶Zn 9%(质量分数)薄膜的光学带隙1.41eV,本征吸收边873nm发生红移,Sn2S3薄膜的光吸收系数均达到105cm-1。     

Bi2O3薄膜的制备及其电阻开关特性的研究

电阻式存储器由于具有众多的优点有望成为最有前景的下一代高速非挥发性存储器的选择之一.实验利用射频磁控溅射法在重掺硅上沉积了Bi2O3薄膜,并对该薄膜的结晶状态和Au/Bi2O3/n+Si/Al结构的电阻开关特性进行了研究.XRD分析结果表明,射频磁控溅射法沉积所得的Bi2O3薄膜结晶性能好,(201)取向明显.I-V曲线测试结果表明,Au/Bi2O3/n+Si/Al结构具有单极性电阻开关特性.通过对不同厚度Bi2O3薄膜的Au/Bi2O3/n+Si/Al结构I-V特性比较发现,随着薄膜厚度的增加,电阻开关的Forming、Set和Reset阈值电压均随之增加.对于Bi2O3薄膜厚度为31.2 nm的Au/Bi2O3/n+Si/Al结构,其Forming、Set和Reset阈值电压均低于4 V,符合存储器低电压工作的要求.     

化学浴法Cu2S纳米晶薄膜的制备及其光学特性研究

利用化学浴沉积法,以EDTA为络合剂,CuSO4·5H2O和Na2S2O3为前驱体溶液制备了硫化亚铜纳米薄膜,用FESEM、XRD、光学显微镜研究了前驱体浓度、络合剂的浓度、溶液的pH值、反应温度等因素对硫化亚铜纳米薄膜的表面形貌、晶粒大小与晶体结构的影响.结果表明,在最佳的生长条件下可以制备晶粒匀一、结构致密的硫化亚铜纳米薄膜,紫外可见吸收光谱表明硫化亚铜薄膜具有一定的透光性,并对红外光有很好屏蔽的作用.     

SrBi2Nb2O9的PLD制备及其非线性光学特性

利用脉冲激光沉积(PLD)方法在MgO(100)基片上生长了SrBi2Nb2O9薄膜.XRD分析表明在MgO基片上生长的薄膜呈(115)单一取向,具有良好的结晶性;XPS数据分析得到薄膜中Sr、Bi和Nb的原子比约为122.05.利用Z扫描技术对薄膜的三阶非线性光学性质进行了测量,通过开孔(Open-aperture)和小孔(Close-aperture)的测量,计算出三阶非线性光学极化率的实部Rex(3)和虚部Imx(3)分别为4.139×10-7eSu,1.104×10-7eSu.     

阳离子部分取代Cu2ZnSnS4的研究进展

P型半导体Cu_2ZnSnS_4(CZTS)由于具有最佳的直接带隙(1.0~1.5eV)、高的光吸收系数(超过104 cm~(-1))以及丰富、无毒的元素组成,使其成为商业化低成本太阳能电池最有希望的候选材料之一。然而,材料本身的一些缺陷制约了CZTS薄膜太阳能电池效率的提高。为了提高CZTS薄膜太阳能电池的效率,研究者们使用其他阳离子部分取代Cu、Zn或Sn来改善CZTS的缺陷。从CZTS的3种不同取代位置出发,综述了近年来各种阳离子部分取代CZTS的研究进展,同时对阳离子部分取代CZTS材料的发展前景进行了展望。     

Growth of Cu2ZnSnS4 thin films using sulfurization of stacked metallic films

We fabricated Cu₂ZnSnS₄ (CZTS) thin films through sulfurization of stacked metallic films. Three types of Cu-Zn-Sn metallic films, i.e., Cu-rich, Cu-correct and Cu-poor precursor films were sputtered onto Mo-coated glass. The sulfurization of stacked Cu-Zn-Sn alloy films was performed at a relatively high temperature, 570 °C, with S-powder evaporation. CZTS films from Cu-rich and Cu-correct precursors showed a Cu_2 − xS phase on the film surface, while CZTS films from Cu-poor precursors didn't show the Cu_2 − xS phase. However, all films didn't exhibit any extra secondary phase and exhibited good crystalline textures even with Cu-ratio differences in metallic precursor films. Fabricated CZTS films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman scattering measurements. SEM cross-section images of CZTS films showed that Cu-poor CZTS films were grown with more smooth film surface compared with other types of CZTS films.     

Aqueous bath process for deposition of Cu2ZnSnS4 photovoltaic absorbers

Chemical bath deposition and ion exchange were used to incorporate copper, zinc, tin and sulfur into a thin film precursor stack. The stack was then sulfurized to form the photovoltaic absorber material Cu₂ZnSnS₄ (CZTS). The morphology and elemental composition of the films at each process stage were analyzed by Auger electron spectroscopy and scanning electron microscopy, and the structural and optical properties of the sulfurized film were determined by a combination of X-ray diffraction, Raman scattering, and diffuse reflectance UV-Vis spectroscopy. Compositionally uniform microcrystalline CZTS with kesterite structure and a bandgap of 1.45 eV were observed. A preliminary solar cell device was produced exhibiting photovoltaic and rectifying behavior.     

氮掺杂对SnO2薄膜光电性能的影响

SnO2薄膜具有透明导电的特性,因而被制成透明电极而广泛应用于平板显示器和太阳能电池中。研究表明,经掺杂的薄膜具有更优异的光电性能,然而传统的掺杂元素Sb,Te或F较为昂贵且有毒性,因此,掺氮将有望解决上述问题。本文利用反应射频磁控溅射法制备出不同氧含量的SnO2以及氮掺杂SnO2薄膜,并分析了薄膜的形貌结构及光电性能。结果表明:薄膜沉积过程中氧分压和氮掺杂对薄膜性能影响较大。在SnO2薄膜中,晶粒呈包状形态,随着氧分压的增加,晶粒取向从(101)转向(110)方向,晶粒尺寸逐渐变小,可见光透光率提升到80%以上,光学带隙增加到4.05 eV;在氮掺杂SnO2薄膜中,晶粒呈四棱锥形态,晶粒取向为(101)方向,随着氧分压的增加,可见光的透过率同样提升到80%以上,光学带隙增加到3.99 eV。SnO2薄膜和氮掺杂SnO2薄膜的电阻率最低分别达到1.5×10-1和4.8×10-3Ω.cm。     

Cu2ZnSnS4纳米颗粒及其薄膜的制备与表征

采用热注入法,在油胺(OLA)中合成出Cu2ZnSnS4(CZTS)纳米颗粒,并在玻璃衬底上制备了薄膜,研究了不同合成温度对纳米颗粒生成的影响.通过X射线衍射仪、拉曼光谱仪、透射电子显微镜、扫描电子显微镜、紫外可见分光光度计对所得纳米晶材料的结构与成分、颗粒大小与形貌、光吸收谱进行了测试分析.研究结果表明:采用热注入法的最佳合成温度在260℃左右,该温度下生成的多晶CZTS纳米颗粒尺寸约10 nm,分散性良好,光学禁带宽度约1.5 eV.     

Cu2ZnSnS4 films by paste coating and their optoelectronic properties

Cu₂ZnSnS₄ (CZTS) thin films were prepared by a paste coating method as the absorb layer of solar cells. This method is more eco-friendly using ethanol as solvent and more convenient than traditional sol–gel method. The effects of sulfurization temperature on properties of thin film were studied. The results of X-ray diffraction and Raman spectroscopy showed the formation of kesterite structure of CZTS films. The scanning electron microscopy images revealed that CZTS thin film obtained at 550 °C were compact and uniform. The optical band gap of the CZTS film was about 1.5 eV, and the CZTS film had an obvious optoelectronic response. Moreover, CZTS solar cell was prepared with a conversion efficiency of 0.47 %.     

Spray pyrolyzed β-In2S3 thin films: Effect of postdeposition annealing

Indium sulfide thin films prepared using spray pyrolysis, with In/S ratio 2/3 in the solution, were annealed in vacuum at 300 and 400 °C. The effect of this treatment on properties of the films was studied using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, optical absorption, transmission and electrical measurements. Optical constants of the films were calculated using the envelope method. Annealing did not affect the optical properties of the film much, but the resistivity of the films showed a drastic decrease and the grain size increased. In₂S₃ thin films have potential use as buffer layer in photovoltaic heterojunction devices.     

Fabrication and characterization of Cu2ZnSnS4 thin films deposited by spray pyrolysis technique

We have investigated synthesis conditions and some properties of sprayed Cu₂ZnSnS₄ (CZTS) thin films in order to determine the best preparation conditions for the realization of CZTS based photovoltaic solar cells. The thin films are made by means of spraying of aqueous solutions containing copper chloride, zinc chloride, tin chloride and thiourea on heated glass substrates at various temperatures. In order to optimize the synthesis conditions of the CZTS films, two series of experiments are performed. In the first series the sprayed duration was fixed at 30 min and in the second it is fixed at 60 min. In each series, the substrate temperature was changed from 553°K to 633°K. The X-ray diffraction shows, on one hand, that the best crystallinity was obtained for 613°K as substrate temperature and 60 min as sprayed duration. On the other hand, these CZTS films exhibit the kesterite structure with preferential orientation along the [112] direction. Atomical Force Microscopy was used to determine the grain sizes and the roughness of these CZTS thin film. After the annealing treatment, we estimated the optical band-gap energy of the CZTS thin film exhibiting the best crystallinity as 1.5 eV which is quite close to the optimum value for a solar cell.     

Sulfurization time effects on the growth of Cu2ZnSnS4 thin films by solution method

Cu₂ZnSnS₄ (CZTS) films were obtained by sulfurizing (Cu, Sn) S/ZnS structured precursors prepared by a combination of the successive ionic layer absorption and reaction method and the chemical bath deposition method, respectively. The effect of sulfurization time on structure, composition and optical properties of these CZTS thin films was studied. The results of energy dispersive spectroscopy indicate that the annealed CZTS thin films are of Cu-poor and Zn-rich states. The X-ray diffraction studies reveal that Cu_2?x S phase exists in the annealed CZTS thin film prepared by sulfurization for 20 min, while the Raman spectroscopy analysis shows that there is a small Cu₂SnS₃ phase existing in those by sulfurization for 20 and 40 min. The band gap (E _g ) of the annealed CZTS thin films, which are determined by reflection spectroscopy, varies from 1.49 to 1.56 eV depending on sulfurization time. The best CZTS thin film is the one prepared by sulfurization for 80 min, exhibiting a single kesterite structure, dense morphology, ideal band gap (E _g  = 1.55 eV) and high optical absorption coefficient (>10⁴ cm^?1).     

Optical properties change in amorphous (As2S3)0.87Sb0.13 thin films by photo and thermal induced process

Exposure with above band gap light and thermal annealing at a temperature near to glass transition temperature, of thermally evaporated amorphous (As₂S₃)_0.87Sb_0.13 thin films of 1 μm thickness, were found to be accompanied by structural effects, which in turn, lead to changes in the optical properties. The optical properties of thin films induced by illumination and annealing were studied by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Photo darkening or photo bleaching was observed in the film depending upon the conditions of the light exposure or annealing. These changes of the optical properties are assigned to the change of homopolar bond densities.