低温超薄高效Cu(In,Ga)Se2太阳电池的实现

衬底温度保持恒定, 在Se气氛下按照一定的元素配比顺序蒸发Ga, In, Cu制备厚度约为0.7 μrm的Cu(In_0.7Ga_0.3)Se₂ (CIGS)薄膜. 利用X射线衍射仪分析薄膜的晶体结构及物相组成, 扫描电子显微镜表征薄膜形貌及结晶质量, 二次离子质谱仪测试薄膜内部元素分布, 拉曼散射谱 分析薄膜表面构成, 带积分球附件的分光光度计测量薄膜光学性能. 研究发现在Ga-In-Se预制层内, In主要通过晶界扩散引起Ga/(Ga+In)分布均匀化. 衬底温度高于450 ℃时, 薄膜呈现单一的Cu(In_0.7Ga_0.3)Se₂相; 低于400℃, 薄膜存在严重的Ga的两相分离现象, 且高含Ga相主要存在于薄膜的上下表面; 低于300 ℃, 薄膜结晶质量进一步恶化. 薄膜表层的高含Ga相Cu(In_0.5Ga_0.5)Se₂以小晶粒形式均匀分布于薄膜表面, 增加了薄膜的粗糙度, 在电池内形成陷光结构, 提高了超薄电池对光的吸收. 加上带隙值较小的低含Ga相的存在, 使电池短路电流密度得到较大改善. 衬底温度在550 ℃–350 ℃变化时, 短路电流密度J_SC是影响超薄电池转换效率的主要因素; 而衬底温度T_sub低于300 ℃时, 开路电压V_OC和填充因子FF降低已成为电池性能减退的主要原因. T_sub为350 ℃时制备的0.7 μm左右的超薄CIGS电池转换效率达到了10.3%. 关键词： 2薄膜')" href="#">Cu(In,Ga)Se₂薄膜 衬底温度 超薄 太阳电池     

硒化前后电沉积贫铜和富铜的Cu(In1-xGax)Se2薄膜成分及结构的比较

采用电沉积法获得了接近化学计量比的贫铜和富铜的Cu（In_1-xGa_x）Se₂（CIGS）预置层,研究比较了两种预置层及其硒化处理后的成分和结构特性.得到了明确的实验证据证明,硒化后富铜薄膜中的Cu_xSe相会聚集凝结成结晶颗粒分散在表面.研究表明：在固态源硒化处理后,薄膜成分基本不变;当预置层中原子比Cu/（In+Ga）<11时,硒化后薄膜表面存在大量的裂纹;而当Cu/（In+Ga） >12时,可以消除裂纹的产生,形成等轴状小晶粒;富铜预置层硒化时蒸发沉积少量In,Ga和Se后,电池效率已达到68%;而贫铜预置层硒化后直接制备的电池效率大于2%,值得进一步深入研究. 关键词： 1-xGa_x）Se₂薄膜')" href="#">Cu（In_1-xGa_x）Se₂薄膜 电沉积 硒化处理 贫铜或富铜薄膜     

预制层溅射气压对CIGS薄膜结构及器件的影响

研究了金属预制层制备过程中溅射气压对Cu(In_1-xGa_x)Se₂(CIGS)薄膜及电池器件性能的影响.通过调节溅射气压改变预制层的结晶状态及疏松度与粗糙度,在合适的预制层结构下,活性硒化热处理过程中,可使Ga有效地掺入到薄膜中形成优质的CIGS固溶体.高溅射气压会使预制层过于致密,呈现非晶态趋势.经活性硒化热处理后,CIGS薄膜容易产生CIS与CGS"两相分离"现象,从而导致CIGS薄膜太阳电池的开路电压和填充因子降低,电池转换效率由10.03%降低到5.02%.     

电沉积Cu-In-Ga金属预制层的硒硫化研究

以H₂S气体作为硫源、固态蒸发硒蒸气作为硒源对电沉积Cu-In-Ga金属预制层进行硒硫化处理. 通过电沉积Cu-In-Ga金属预制层在不同衬底温度下硒化、硫化和硒硫化的对比实验,发现CuInS₂相和CuIn（S,Se）₂相优先生成,抑制了CuInSe₂相的生成,促使InSe相薄膜向内部扩散,减弱了薄膜两相分离现象. 采用先硒化后硒硫化处理工艺优化了Cu（In,Ga）（S,Se）₂薄膜的制备工艺,在250 ℃预硒化得到了开路电压为570 mV的太阳电池,在更高的预硒化温度得到了较大短路电流的太阳电池,最终优化得到了效率达到10.4%的电池器件. 关键词： 电化学沉积 Cu-In-Ga金属预制层 硒硫化处理 2薄膜')" href="#">Cu(In,Ga)(S,Se)₂薄膜     

Stage2沉积速率对低温生长CIGS薄膜特性及器件的影响

研究了三步法第二步沉积速率对低温生长Cu(In,Ga)Se₂薄膜结构、 电学特性和器件特性的影响. 通过改变第二步沉积速率发现, 提高沉积速率可以显著促进薄膜晶粒生长, 提高晶粒紧凑程度降低晶界复合, 同时有效改善两相分离现象, 提高电池的开路电压和短路电流, 有助于Cu(In,Ga)Se₂电池光电转换效率的提高. 但同时研究表明, 随着第二步沉积速率的增加, 会促进暂态Cu_2-xSe晶粒的生长, 引起Cu(In,Ga)Se₂薄膜表面粗糙度增大, 并阻碍Na向Cu(In,Ga)Se₂薄膜表面的扩散, 造成施主缺陷钝化效应降低, 薄膜载流子浓度下降和电阻率升高, 且过高的沉积速率会引起电池内部复合增加并产生分流路径, 造成开路电压下降进而引起电池效率恶化. 最终, 通过最佳化第二步沉积速率, 在衬底温度为420℃时, 得到最高转换效率为11.24%的Cu(In,Ga)Se₂薄膜太阳电池.     

衬底对Cu(In,Ga)Se2薄膜织构的影响

分别在苏打石灰玻璃、Mo箔、无择优取向的Mo薄膜以及(110)择优取向的Mo薄膜四种不同衬底上，采用共蒸发工艺沉积约2 μm厚的Cu(In,Ga)Se₂薄膜，用X射线衍射仪测量薄膜的织构，研究衬底对Cu(In,Ga)Se₂薄膜织构的影响.在以上四种衬底上沉积的Cu(In,Ga)Se₂薄膜的(112)衍射峰强度依次逐渐减弱，(220/204)衍射峰从无到有且强度逐渐增强.在苏打石灰玻璃和Mo箔衬底上的Cu(In,Ga)Se_{2关键词： 择优取向 Cu(In 2}薄膜')" href="#">Ga)Se₂薄膜 太阳电池     

Cu(In,Ga)Se2 薄膜在共蒸发"三步法"中的相变过程

CIGS薄膜的结晶相是制备高质量薄膜的关键问题. 本文采用共蒸发"三步法"工艺沉积Gu(In, Ga)Se₂ (CIGS) 薄膜, 通过X射线衍射仪 (XRD) 和X射线荧光光谱仪 (XRF)、扫描电镜 (SEM) 结合的方法详细研究了"三步法"工艺的相变过程, 并制备出转换效率超过15% 的 CIGS 薄膜太阳电池. 关键词： CIGS薄膜 共蒸发三步法 相变过程     

空间用GaInP/GaAs/In0.3Ga0.7 As(1 eV)倒装三结太阳电池研制

采用阶变缓冲层技术 (step-graded) 外延生长了具有更优带隙组合的倒装GaInP/GaAs/In_0.3Ga_0.7As(1.0 eV) 三结太阳电池材料, TEM和HRXRD测试表明晶格失配度为2%的In_0.3Ga_0.7As 底电池具有较低的穿透位错密度和较高的晶体质量, 达到太阳电池的制备要求. 通过键合、剥离等工艺制备了太阳电池芯片. 面积为 10.922 cm² 的太阳电池芯片在空间光谱条件下转换效率达到32.64% (AM0, 25 ℃), 比传统晶格匹配的 GaInP/GaAs/Ge(0.67 eV) 三结太阳电池的转换效率提高3个百分点. 关键词： 太阳电池 三结 倒装结构     

新型硒化锑材料及其光伏器件研究进展

硒化锑(Sb₂Se₃)是一种二元单相化合物, 原料储量大、毒性低、价格便宜; 同时其禁带宽度合适(～1.15 eV), 吸光系数大(>10⁵ cm^-1), 长晶温度低, 非常适合制作新型低成本低毒的薄膜太阳能电池, 理论光电转换效率可达30%以上. 目前文献报道的Sb₂Se₃薄膜太阳能电池效率已达3.7%, 初步证明了Sb₂Se₃材料在薄膜太阳能电池应用方面的巨大潜力. 本文综述了近年来Sb₂Se₃太阳能电池的研究进展, 着重介绍了Sb₂Se₃的材料特性和薄膜制备及相关理论研究, 阐述了不同结构电池器件的研究进展, 并对其发展趋势进行了展望.     

硒化前后电沉积贫铜和富铜的Cu(In1-xGax)Se2薄膜成分及结构的比较

采用电沉积法获得了接近化学计量比的贫铜和富铜的Cu(In1-xGax)Se2(CIGS)预置层,研究比较了两种预置层及其硒化处理后的成分和结构特性.得到了明确的实验证据证明,硒化后富铜薄膜中的CuxSe相会聚集凝结成结晶颗粒分散在表面.研究表明:在固态源硒化处理后,薄膜成分基本不变;当预置层中原子比Cu/(In+Ga)<1.1时,硒化后薄膜表面存在大量的裂纹;而当Cu/(In+Ga) >1.2时,可以消除裂纹的产生,形成等轴状小晶粒;富铜预置层硒化时蒸发沉积少量In,Ga和Se后,电池效率已达到6.8%;而贫铜预置层硒化后直接制备的电池效率大于2%,值得进一步深入研究.     

Flexible Cu（In,Ga）Se2 Thin-Film Solar Cells on Polyimide Substrate by Low-Temperature Deposition Process

The electrical and structural properties of polycrystalline Cu（In, Ga）Se2 films grown on polyimide （PI） substrates below 400℃ via one-stage and three-stage co-evaporation process have been investigated by x-ray diffraction spectra （XRD）, scanning electron microscopy （SEM） and Hall effect measurement. As shown by XRD spectra, the stoichiometric CIGS films obtained by one-stage process exhibit the characteristic diffraction peaks of the （In0.68Ga0.32）2Se3 and Cu（In0.7Ga0.3）2Se. It is also found that the film structures indicate more columnar and compact than the three-stage process films from SEM images. The stoichiometric CIGS films obtained by three-stage process exhibit the coexistence of the secondary phase of （In0.68Ga0.32）2Se3, Cu2-xSe and Cu（In0.7Ga0.3）2Se. High net carrier concentration and sheet conductivity are also observed for this kind of film, related to the presence of Cu2-xSe phase. As a result, when the CIGS film growth temperature is below 400℃, the three-stage process is inefficient for solar cells. By using the one-stage co-evaporation process, the flexible CIGS solar cell on a PI substrate with the best conversion efficiency of 6.38% is demonstrated （active area 0.16cm^2）.     

Structural properties of CuInSe2 films prepared by selenization of metallic precursors on MoNx film substrates

The aim of this work was to study the effect of MoN_x film substrates on the structural properties of CuInSe₂ films prepared by selenization of metallic Cu-In alloy precursors. MoN_x films were prepared by reactive dc-magnetron sputtering. All the CuInSe₂ films exhibit single phase chalcopyrite structure with (1 1 2) preferred orientation, which can be explained by the reduction of lattice mismatch between CuInSe₂ and MoN_x. The bulk composition of selenized CuInSe₂ films are near stoichiometric, but the surface composition analysis suggests Cu deficiency on surface area. Furthermore, ordered defect compound, CuIn₂Se_3.5 is found on the surface of CuInSe₂ films. The results will be helpful for fabricating Cd-free ZnO buffer layer CuInSe₂ and Cu(In_1−xGa_x)Se₂ based thin film solar cells.     

In0.3Co4Sb12-xSex 方钴矿热电材料的制备和热电性能

用熔融退火结合放电等离子烧结法制备了In_0.3Co₄Sb_12-xSe_x(x=0—0.3)方钴矿热电材料,探讨了In的存在形式,系统研究了Se掺杂量对结构和热电性能的影响.结果表明:In可以填充到方钴矿二十面体空洞处,过量In在晶界处形成InSb第二相,Se对Sb的置换使晶格常数减小,In填充上限降低;In_0.3Co₄Sb_12-xSe_x样品呈n型传导,随着Se掺杂量的增大,载流子浓度降低,电导率下降,Seebeck系数增大,功率因子有所降低;由于在结构中引入了质量波动及晶格畸变,适量的Se掺杂可以大幅降低材料晶格热导率;样品In_0.3Co₄Sb₁₂和In_0.3Co₄Sb_11.95Se_0.05的最大ZT值均达到1.0以上. 关键词： 掺杂 填充式方钴矿 热电性能     

Material and device properties of Cu(In,Ga)Se2 absorber films prepared by thermal reaction of InSe/Cu/GaSe alloys to elemental Se vapor

The aim of this work was to study the influence of selenization temperature on the morphological and structural properties of CuIn_1−xGa_xSe₂ (CIGS) polycrystalline thin films prepared by a two-step method. The compound and metallic precursors were deposited sequentially using GaSe, InSe and Cu sources by thermal evaporation. These identical InSe/Cu/GaSe precursors are then selenized with Se vapor in a vacuum system. All the CIGS films showed chalcopyrite structure and presence of secondary phases observed at low temperatures. High temperature treatment led to better crystalline and an increase in grain size. Solar cell devices are fabricated and J–V measurements performed under AM1.5 global solar spectra conditions at 25 °C are presented.     

Spectromicroscopic investigation of (NH4)2S treated polycrystalline Cu(In1−xGax)Se2

Device-grade polycrystalline thin-film Cu(In_1−xGa_x)Se₂ was treated with (NH₄)₂S at 60°C to determine the resulting microscopic surface composition/morphology. Scanning electron microscopy was used to evaluate the resultant macroscopic surface morphology. Modification of the surface and grain boundary chemistry of the Cu(In_1−xGa_x)Se₂ polycrystalline films was investigated with scanning photoemission spectromicroscopy. The submicrometer lateral resolution of this technique allows us to directly characterize not only the surface chemistry of the treated films on the submicron scale, but also to probe the grain boundary chemistry. Chemical maps depicting the distribution of chemical species on the surface and at grain boundaries were obtained by monitoring the S 2p, Se 3d, In 4d/Ga 3d and Cu 3d (valence band) photoelectrons while scanning the sample. Background maps were also acquired of each of the peak energies to separate chemical contrast from topographic contrast. Results show that S has been incorporated at the surface, possibly creating a wider bandgap Cu(In_1−xGa_x)(Se_1−yS_y)₂ surface layer, and along the grain boundaries. The purpose of this investigation is to find an environmentally safe replacement for the toxic CdS overlayer commonly used for heterojunction devices without sacrificing overall device performance and reliability.     

金属有机物化学气相沉积法生长Ga2（1-x）In2xO3薄膜的结构及光电性能研究

采用金属有机物化学气相沉积（MOCVD）法在蓝宝石（0001）衬底上制备出了Ga_2（1-x）In_2xO₃（x=01—09）薄膜,研究了薄膜的结构、电学和光学特性以及退火处理对薄膜性质的影响.测量结果表明：当In组分x=02时,样品为单斜β-Ga₂O₃结构;x=05的样品,薄膜呈现非晶结构,退火处理后薄膜结构得到明显的改善 关键词： 金属有机物化学气相沉积 2（1-x）In_2xO₃薄膜')" href="#">Ga_2（1-x）In_2xO₃薄膜 蓝宝石衬底 退火     

Short-range order analysis and some physical properties of InxSe1−x glasses

Bulk In_xSe_1−x (with x=5-25 at%) glasses were prepared using the melt-quench technique. Short range order(SRO) was examined by the X-ray diffraction using Cu(k_α) radiation in the wave vector interval 0.28≤k≤6.5 A⁰⁻¹.The SRO parameters have been obtained from the radial distribution function. The inter-atomic distance obtained from the first and second peak are r₁=0.263 and r₂=0.460 nm, which is equivalent In-Se and Se-Se bond length. The fundamental structural unit for the studied glasses is In₂Se₃ pyramid. Using the differential scanning calorimetry (DSC), the crystallization mechanism of In_xSe_1−x chalcogenide glass has been studied. The glass transition activation energy (E_g) is 289±0.3 kj/mol.There is a correlation amongst the glass forming ability, bond strength and the number of lone pair electrons. The utility of the Gibbs-Di Marzio relation was achieved by estimating T_g theoretically.     

The effect of addition of gallium on the thermal stability and crystallization kinetic parameters of GaxSe100−x glass system

Differential scanning calorimetry (DSC) technique was used to study the kinetics of amorphous to crystalline transformation for Ga_xSe_100−x glass system (x=0, 2.5 and 5 at%). The kinetic parameters of Ga_xSe_100−x glass system under non-isothermal conditions are analyzed by the model-free and model-fitting models at different constant heating rates (5-50 K/min). A strong heating rate dependence of the effective activation energy of crystallization was observed. The analysis of the present data shows that the effective activation energy of crystallization is not constant but varies with the degree of crystallization and with temperature as well. The crystallization mechanisms examined using the local Avrami exponents indicate that one mechanism (volume nucleation with one-dimensional growth) is responsible for the crystallization process for heating rates 5-50 K/min for Se glass and two mechanisms (volume nucleation with two- and one-dimensional growth) are working simultaneously during the amorphous-crystalline transformation of the Ga_2.5Se_97.5 and Ga₅Se₉₅ glasses (5-50 K/min). The reaction model that may describe crystallization process of all the compositions of Ga_xSe_100−x glass system is Avrami-Erofeev model (g(α)=[−ln(1−α)]^1/n) with n=2 for Se glass. While for Ga_2.5Se_97.5 and Ga₅Se₉₅ glasses, the values of n are equal to 3 and 2 for the heating rates 5-20 and 35-50 K/min, respectively. A good agreement between the experimental and the reconstructed (α-T) curves has been achieved. The transformation from amorphous to crystalline phase in Ga_xSe_100−x glass system demonstrates complex multi-step involving several processes.