共蒸发三步法制备CIGS薄膜的性质

采用PID温度控制器控制共蒸发设备中蒸发源及衬底加热的温度,以三步法工艺制备CIGS(Cu(In,Ga)Se2)薄膜,通过恒功率加热衬底测试温度的变化,可实现在线组分监测,得到CIGS薄膜的组成重现性很好.CIGS薄膜的表面光洁,粗糙度多数小于10nm.但是组成相同的CIGS薄膜,其结晶择优取向可能不同,主要有(112)和(220)/(204)两种;其结晶形貌也有很大的不同,晶粒粗大且成柱状的薄膜电池效率高,虽然从Cu/(In+Ga)＜1的组成可以认为CIGS薄膜为贫Cu结构,但Hall测试多数CIGS薄膜呈p型,少数呈n型.     

聚酰亚胺衬底CIGS薄膜附着性的改善

为改善聚酰亚胺(PI)衬底Cu(In,Ga)Se2(CIGS)薄膜的附着性,提出在NaF沉积前预先在Mo层上蒸发沉积100nm厚的In-Ga-Se(IGS)薄膜的新掺Na工艺。结果表明:这种IGS-NaF-CIGS式新工艺可显著改善CIGS薄膜的附着,而且CIGS薄膜材料和器件特性没有显著退化;新工艺促进了NaInSe2的生成,减少了In-Se二元相的残余,但也造成薄膜电阻率的升高和电池填充因子的下降,进而导致制备的PI衬底CIGS电池的转换效率由9.8%降至9.0%。综合考虑附着性的改善和器件效率的轻微下降,新工艺利大于弊,有很好的应用前景。     

CIGS薄膜(InGa)2Se3-富Cu-富In(Ga)的演变

采用三步共蒸发工艺顺序沉积铜铟镓硒(CuInGaSe2,CIGS)薄膜.薄膜的厚度、组份、晶相结构分别由台阶仪、X射线荧光光谱仪(XRF)和X射线衍射仪(XRD)来表征.在(In,Ga)2Se3预制层-富Cu相的演变过程中,依次发生以下相变:Cu(In,Ga)5Se8、Cu(In,Ga)3Se5、Cu2(In,Ga)4Se7(或Cu(In,Ga)2Se3.5)、Cu(In,Ga)Se2(液相CuxSe).在富Cu相-富In(Ga)相的演变过程中,依次发生以下相变:Cu(In,Ga)Se2(液相CuxSe)、Cu2(In,Ga)4Se7(或Cu(In,Ga)2Se3.5)、Cu(In,Ga)3Se5、Cu(In,Ga)5Se8.对这两个演变过程中薄膜的生长机理和结构特性进行了讨论.     

掺Na制备柔性聚酰亚胺衬底CIGS薄膜太阳电池

研究了Na掺入对低温沉积柔性聚酰亚胺(PI)衬底Cu(In,Ga)Se2(CIGS)薄膜的结构和电学特性影响。研究结果表明:Na元素的掺入使Ga元素的扩散受到了阻滞,但对CIGS薄膜晶粒尺寸没有明显的影响,少量的Na可提高CIGS薄膜的载流子浓度和降低电阻率;Na的掺入可明显提高CIGS薄膜太阳电池的器件特性,通过优化掺Na工艺,制备的柔性PI衬底—CIGS薄膜太阳电池的最高转换效率达到10.4%。     

CdS薄膜的结构特性及其对Cu(In,Ga)Se2(CIGS)薄膜太阳电池的影响

报道了CdS薄膜的CBD法沉积及其结构特性,其中的水浴溶液包括硫脲、乙酸镉、乙酸铵和氨水溶液.研究了水浴溶液的pH值、温度、各反应物溶液的浓度和滴定硫脲与倾倒硫脲等基本工艺参数对CdS薄膜结构特性的影响.其中,溶液的pH值对CdS薄膜的特性起着关键的作用.XRD图显示了随着溶液pH值的变化,薄膜的晶相由六方相向立方相转变.CdS薄膜的这两种晶相对CIGS薄膜太阳电池性能的影响不相同.c-CdS(立方相的CdS)与CIGS之间的晶格失配和界面态密度分别为1.419%和8.507×1012cm-2,而h-CdS(六方相的CdS)与CIGS之间的晶格失配和界面态密度则分别为32.297%和2.792×1012cm-2.高效CIGS薄膜太阳电池需要的是立方相CdS薄膜.     

硒化温度对Cu(In, Al)Se2薄膜结构和光学性质的影响

采用了磁控溅射制备Cu-In-Al金属前驱体薄膜,后硒化快速退火得到铜铟铝硒(Cu(In,Al)Se2,CIAS)薄膜.研究了硒化温度对CIAS薄膜晶体结构和光学性质的影响.研究发现CIAS薄膜的晶体结构依赖于硒化温度,其禁带宽度随硒化温度升高发生红移.研究结果表明,CIAS薄膜的最佳硒化温度为540℃,其晶体结构为纯黄铜矿结构,禁带宽度为.34 eV,对应太阳电池理论最大效率的吸收层材料禁带宽度     

铜铟镓硒薄膜太阳电池研究进展和挑战

铜铟镓硒(Cu（In,Ga）Se₂,CIGS)太阳电池产业化受到全世界广泛关注。作为高转换效率薄膜电池,其效率可与晶硅电池相比,目前最高效率达到23.35%。对于小面积实验室电池而言,研究重点是精确控制吸收层的化学计量比和效率;对于工业化生产而言,除化学计量比和效率外,成本、重现性、产出和工艺兼容性在商业化生产中至关重要。重点介绍了不同制备工艺、吸收层组分梯度调控、碱金属后沉积处理、宽带隙无镉缓冲层、透明导电层和柔性衬底等研究进展。从CIGS电池的效率来看,将实验室创纪录的高效电池技术转移到平均工业生产水平带来显而易见的挑战。     

新型CIGS阻挡层多横向界面Mo的特性及对器件性能的影响

采用磁控溅射方法,在不锈钢箔上制备多横向界 面Mo(M-Mo,multi-transverse interface Mo)和单横向界面Mo(S-Mo)薄 膜,并利用共蒸发三步法分别在M-Mo和S-Mo薄膜上制备Cu(In,Ga)Se₂(CIGS)薄膜及 器件。通过二次离子质谱仪(SIMS)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)研究了不同 结构的Mo薄膜对CIGS影响。通过I-V测试,表征M-Mo和S -Mo作为背电极的CIGS电池电学性能。XRD结果显示,M-Mo和S-Mo 薄膜均以(110)为择优取向。SEM结果显示,M-Mo薄膜相对 于S-Mo,薄膜晶粒 较小,粗糙度较大。J-V测试结果显示,M-Mo薄膜作为背 电极的电池的开路电压Voc、短路电流J sc和填充因子(FF)均有所提高。     

CdS薄膜的结构特性及其对Cu(In,Ga)Se2(CIGS)薄膜太阳电池的影响

报道了CdS薄膜的CBD法沉积及其结构特性,其中的水浴溶液包括硫脲、乙酸镉、乙酸铵和氨水溶液.研究了水浴溶液的pH值、温度、各反应物溶液的浓度和滴定硫脲与倾倒硫脲等基本工艺参数对CdS薄膜结构特性的影响.其中,溶液的pH值对CdS薄膜的特性起着关键的作用.XRD图显示了随着溶液pH值的变化,薄膜的晶相由六方相向立方相转变.CdS薄膜的这两种晶相对CIGS薄膜太阳电池性能的影响不相同.c-CdS(立方相的CdS)与CIGS之间的晶格失配和界面态密度分别为1.419%和8.507×1012cm-2,而h-CdS(六方相的CdS)与CIGS之间的晶格失配和界面态密度则分别为32.297%和2.792×1012cm-2.高效CIGS薄膜太阳电池需要的是立方相CdS薄膜.     

CdS薄膜的真空热蒸发制备及在CIGS薄膜太阳电池中的应用

采用真空热蒸发(VTE)的方法制备了CdS多晶薄膜,研究了不同衬底温度对其微观结构与光电性能的影响。结果显示,不同衬底温度下制备的CdS薄膜均属于六方相多晶结构且具有(002)择优取向;随着衬底温度的升高,(002)特征衍射峰强度增加,半高宽变小,相应薄膜结晶度增大;由CdS薄膜的透射光谱可知,在500~1 000nm波段平均透过率均超过80%,光学带隙随着衬底温度的升高而增大(2.44~2.56eV),表明真空热蒸发方法制备的CdS薄膜可以作为CIGS薄膜太阳电池的缓冲层。将真空热蒸发法制备CdS薄膜与磁控溅射法制备CIGS薄膜太阳电池相结合,在同一真空室内得到了CIGS薄膜太阳电池器件,为CIGS薄膜太阳电池的工业化推广提供了新途径。     

Cu(In,Ga)Se2太阳电池缓冲层ZnS薄膜性质及应用

在含有ZnSO4,SC(NH2)2,NH4OH的水溶液中采用CBD法沉积ZnS薄膜,XRF和热处理前后的XRD测试表明,ZnS沉积薄膜为立方相结构,薄膜含有非晶态的Zn(OH)2.光学透射谱测试表明,制备的薄膜透过率(λ＞500nm)约为90%,薄膜的禁带宽度约为3.51eV.ZnS薄膜沉积时间对Cu(In,Ga)Se2太阳电池影响显著,当薄膜沉积时间在25～35min时,电池的综合性能最好.对比了不同缓冲层的电池性能,采用CBD-CdS为缓冲层的电池转换效率、填充因子、开路电压稍高于CBD-ZnS为缓冲层的无镉电池,但无镉电池的短路电流密度高于前者,两者转换效率相差2%左右.ZnS可以作为CIGS电池的缓冲层,替代CdS,实现电池的无镉化.     

Cu(In,Ga)Se2太阳电池缓冲层ZnS薄膜性质及应用

在含有ZnSO4,SC(NH2)2,NH4OH的水溶液中采用CBD法沉积ZnS薄膜,XRF和热处理前后的XRD测试表明,ZnS沉积薄膜为立方相结构,薄膜含有非晶态的Zn(OH)2.光学透射谱测试表明,制备的薄膜透过率(λ＞500nm)约为90%,薄膜的禁带宽度约为3.51eV.ZnS薄膜沉积时间对Cu(In,Ga)Se2太阳电池影响显著,当薄膜沉积时间在25～35min时,电池的综合性能最好.对比了不同缓冲层的电池性能,采用CBD-CdS为缓冲层的电池转换效率、填充因子、开路电压稍高于CBD-ZnS为缓冲层的无镉电池,但无镉电池的短路电流密度高于前者,两者转换效率相差2%左右.ZnS可以作为CIGS电池的缓冲层,替代CdS,实现电池的无镉化.     

Fabrication of Cu(In,Ga)Se2 thin films by sputtering from a single quaternary chalcogenide target

Single‐layered Cu‐In‐Ga‐Se precursors were fabricated by one‐step sputtering of a single quaternary Cu(In,Ga)Se₂ (CIGS) chalcogenide target at room temperature, followed by post selenization using Se vapor obtained from elemental Se pellets. The morphological and structural properties of both as‐deposited and selenized films were characterized by X‐ray diffraction (XRD), Raman spectroscope and scanning electron microscope (SEM). The precursor films exhibited a chalcopyrite structure with a preferential orientation in the (112) direction. The post‐selenization process at high‐temperature significantly improved the quality of the chalcopyrite CIGS. The CIGS layers after post‐selenization were used to fabricate solar cells. The solar cell had an open‐circuit voltage Voc of 0.422 V, a short‐circuit current density J = 24.75 mA, a fill factor of 53.29%, and an efficiency of 7.95%. Copyright © 2010 John Wiley & Sons, Ltd.     

Reactive Sputtering Process for CuIn1‐xGaxSe2 Thin Film Solar Cells

CuIn_1‐xGa_xSe₂ (CIGS) thin films are grown on Mo/soda lime glass using a reactive sputtering process in which a Se cracker is used to deliver reactive Se molecules. The Cu and (In_0.7Ga_0.3)₂Se₃ targets are simultaneously sputtered under the delivery of reactive Se. The effects of Se flux on film composition are investigated. The Cu/(In+Ga) composition ratio increases as the Se flux increases at a plasma power of less than 30 W for the Cu target. The (112) crystal orientation becomes dominant, and crystal grain size is larger with Se flux. The power conversion efficiency of a solar cell fabricated using an 800‐nm CIGS film is 8.5%.     

Non‐destructive optical analysis of band gap profile,crystalline phase,and grain size for Cu(In,Ga)Se2 solar cells deposited by 1‐stage, 2‐stage,and 3‐stage co‐evaporation

Cu(In,Ga)Se₂ (CIGS) thin films co‐evaporated by 1‐stage, 2‐stage, and 3‐stage processes have been studied by spectroscopic ellipsometry (SE). The disappearance of a Cu_2‐xSe optical signature, detected by real time SE during multistage CIGS, has enabled precise endpoint control. Band gap energies determined by SE as depth averages show little process variation for fixed [Ga]/([In] + [Ga]) atomic ratio, whereas their broadening parameters decrease with increasing number of stages, identifying successive grain size enhancements. Refined SE analysis has revealed band gap profiling only for 3‐stage CIGS. Solar cells incorporating these absorbers have yielded increased efficiencies in correlation with phase control, grain size, and band gap profiling. Copyright © 2013 John Wiley & Sons, Ltd.     

Properties of 19.2% efficiency ZnO/CdS/CuInGaSe2 thin‐film solar cells

We report the growth and characterization of record‐efficiency ZnO/CdS/CuInGaSe₂ thin‐film solar cells. Conversion efficiencies exceeding 19% have been achieved for the first time, and this result indicates that the 20% goal is within reach. Details of the experimental procedures are provided, and material and device characterization data are presented. Published in 2003 by John Wiley & Sons, Ltd.     

利用多光子电离显微术研究铜铟镓硒薄膜太阳电池的微纳米膜层结构

基于超短脉冲激光多光子电离显微成像原理,利 用平均功率50μW、脉冲重复频率1kHz的 50fs激光脉冲,对铜铟镓硒(CIGS)薄膜太阳电池进行深度扫描, 比较分析了单纯钠钙玻璃衬底、镀钼钠钙 玻璃和铜铟镓硒/钼膜层/钠钙玻璃三种不同结构样品飞秒激光电离辐射信号的差别。实验发 现,对应于不同膜 层材料的飞秒激光诱导的电离辐射信号强度明显不同,在钠钙玻璃中电离辐射信号的强度约 为空气本底的 20倍,在Mo背电极层信号强度约为钠钙玻璃衬底的50倍,而CIGS层则出现与其带隙相对应的吸收谷, 谷的强度与空气背景相同,利用多光子电离显微术对太阳电池进行逐点扫描可以对CIGS和Mo 背电极层 的成膜质量、吸收带隙和微纳结构进行精细研究。分析表明,超短脉冲多光子电离显微术对 不同物质边界处 的变化非常敏感,在具有多层结构的复杂器件的微观特性检测方面具有独特的优势。     

The effect of Mo back contact ageing on Cu(In,Ga)Se2 thin‐film solar cells

In this work, we investigate the effect of ageing Mo‐coated substrates in a dry and N₂ flooded cabinet. The influence was studied by preparing Cu(In,Ga)Se₂ solar cells and by comparing the electrical performance with devices where the Mo layer was not aged. The measurements used for this study were current–voltage (J‐V), external quantum efficiency (EQE), secondary ion mass spectroscopy (SIMS) and capacitance–voltage (C‐V). It was concluded that devices prepared with the aged Mo layer have, in average, an increase of 0.8% in efficiency compared with devices that had a fresh Mo layer. Devices with aged Mo exhibited a nominal increase of 12.5 mV of open circuit voltage, a decrease of 1.1 mA/cm⁻² of short circuit current and a fill factor increase of 2.4%. Heat treatment of fresh Mo layers in oxygen atmosphere was also studied as an alternative to ageing and was shown to provide a similar effect to the aged device's performance. Copyright © 2013 John Wiley & Sons, Ltd.     

CdS/Cu(In,Ga)S2 based solar cells with efficiencies reaching 12.9% prepared by a rapid thermal process

In this letter, we report externally confirmed total area efficiencies reaching up to 12.9% for CdS/Cu(In,Ga)S₂ based solar cells. These are the highest externally confirmed efficiencies for such cells. The absorbers were prepared from sputtered metals subsequently sulfurized using rapid thermal processing in sulfur vapor. Structural, compositional, and electrical properties of one of these champion cells are presented. The correlation between the Ga distribution profile and solar cell properties is discussed. Copyright © 2012 John Wiley & Sons, Ltd.