【作者】 邱继军；

【导师】 靳正国；

【作者基本信息】 天津大学 ， 材料学， 2005， 博士

【摘要】 纳米晶太阳能电池(NPC)以其简单的工艺,低廉的成本以及可实现规模化生产等优势成为绿色能源领域的研究热点之一。本文综述了太阳能电池及其光敏化、吸收材料的发展,研究了NPC太阳能电池无机硫属半导体光吸收层薄膜新型化学法的制备。课题选择CdS,CuInS2硫属半导体材料分别作为NPC太阳能电池中缓冲层和光吸收层,采用离子层气相反应法(ILGAR),研究了制备条件对薄膜结构与性能的影响,如阳离子吸附方式、溶剂种类、混合离子浓度及配比、硫化反应温度、热处理温度、时间与气氛、薄膜生长与厚度控制、Ga掺杂等。采用XRD、SEM、UV-Vis、XPS、HALL系统等对薄膜晶型、微结构、化学计量、光学和电学等性能进行了表征。ILGAR法制备CdS薄膜的实验结果表明,以CdCl2为反应物,H2O和CH3CN混合液为溶剂,H2S为硫源所得纳米晶薄膜表面较致密、均匀、附着性好;0.05M阳离子浓度吸附下的平均生长速率为2.8nm/cycle;400℃热处理温度下结构为沿(002)面择优生长的六方铅锌矿。首次采用混合阳离子溶液吸附工艺,以C2H5OH为溶剂,离子浓度比[Cu+]/[In3+]为1.55,硫化温度在40℃,550℃热处理1h可制备出单相、表面致密、粒径均匀、沿(112)面择优取向生长的黄铜矿型纳米晶CuInS2薄膜。随离子浓度配比的变化,薄膜的光吸收系数均高于104 cm-1,禁带宽度Eg在1.30～1.40 eV之间变化,表面电阻、载流子浓度和迁移率分别在50～10?·cm, 1016～1017cm-3,2～7cm2/V·s的范围内可调。Ga掺杂研究结果表明,混合前驱体溶液中[Ga]/[In]低于1时,Ga取代In形成CuIn1-xGaxS2四元单相薄膜;当Ga]/[In]高于1时,Ga和In分别以各自三元相形式独立存在。随[Ga]/[In]的增加,CuIn1-xGaxS2四元单相薄膜的光学禁带宽度变宽,电阻在103～104?/□范围内。更多还原

【Abstract】 In past decades, considerable attention has been given to nanocrystallinephotovoltaic cells (NPC) because of its simple process, low cost and large scaleproduction. In this paper, developments of NPC cells and its absorbers were reviewed,and a novel chemical deposition method-ILGAR was studied to fabricate metalchalcogenide thin films for NPC.CdS and CuInS2 thin films, as buffer and absorber layer respectively, werefabricated by ion layer gas reaction method (ILGAR), and the influence ofpreparation conditions on the film properties was investigated, such as absorptionways of the cations in precursor solution, the type of solvents, the concentration andratio of mixed precursors, sulfidation temperature, heat-treatment temperature, timeand atmosphere, Ga-doping. The characterizations for films were carried out byX-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectronspectrum (XPS), optical absorption spectrum and Hall system.The results show that CdS thin films fabricated by ILGAR method are uniform,compact and good in adhesion to substrate, and growth ratio of the film is 2.8 nm/cycle as [Cd2+]=0.05M. The evolution of structure undergoes from cubic tohexagonal with a preferred orientation along (002) plane after annealing of theas-deposited films at 400 ℃.ILGAR method for CuInS2 films was developed firstly by using ethanol assolvent and mixed cation precursor. Chalcopyrite CuInS2 film with near stoichiometryderived from [Cu+]/[In3+]=1.55, which is uniform, compact and good in adhesion tothe substrates, can be obtained after annealing in Ar atmosphere for 1h. Withincreasing the [Cu+]/[In3+], the absorption coefficients of CuInS2 films are more than104 cm-1, and the band gap changes from 1.40 to 1.30 eV, the resistivity, the carrierconcentration and the mobility is in the range from 50 to 10 ?-cm, 1015 to 1017 cm-3 and 2to 7 cm2/V·s, respectively.In the study of Ga-doping, single phase CuIn1-xGaxS2 thin films can be obtainedas [Ga3+]/[In3+] in mixed cationic solution is below 1, while [Ga3+]/[In3+] is above 1,two ternary compounds CuInS2 and CuGaS2 instead of CuIn1-xGaxS2 occur inannealed films.更多还原