铜含量变化对Cu(In,Ga) Se2薄膜微结构的影响

摘要

The influence of different Cu contents (Cu/(Ga + In) =0.748 ～ 0.982) on the microstructure of Cu (In,Ga)Se2 (CIGS) thin films was reported.The CIGS thin films were grown via a two-step process including DC sputtering deposition of metallic precursor and following selenization.Presence of a series of chalcopyrite diffraction peaks in the X-Ray diffraction (XRD) patterns confirms the existence of chalcopyrite CIGS (CH-CIGS) phase in these CIGS films.The Raman spectra indicate that as the Cu content increases from low to high,the CIGS film sequentially goes through three phase regimes:coexistence of OVC and CH-CIGS phase,single CH-CIGS phase and coexistence of CuxSe and CH-CIGS phase.Moreover,the full width at half maximum of CIGS Raman peaks changes with Cu/(Ga + In) and reaches its minimum near Cu/(Ga + In) =0.9 due to better crystallinity and less disorder.Some empirical FWHM-Cu/(Ga + In) relationships were also observed.These results show that Raman spectroscopy is more sensitive to the microstructure of CIGS film than XRD,and can be used for preliminary estimation of the crystal phases and Cu content of CIGS film in a fast and non-destructive way.%报道了不同的铜含量(Cu/(Ga+ In)=0.748 ～ 0.982)对Cu(In,Ga) Se2 (CIGS)薄膜微结构的影响.文章中的CIGS薄膜采用磁控溅射金属预置层后硒化的方法制备,其X射线衍射谱(XRD)中一系列黄铜矿结构CIGS (CH-CIGS)相的衍射峰确认了CH-CIGS相的存在.对CIGS薄膜拉曼光谱的分析表明,随着铜含量的上升,CIGS薄膜经历了CH-CIGS和有序缺陷化合物(OVC)混合相、CH-CIGS单相、CH-CIGS和CuxSe混合相三种状态.进一步的分析显示,CIGS薄膜拉曼峰的半高宽随铜含量变化,并在Cu/(Ga+ In) =0.9附近时达到最小值,这说明此时CIGS薄膜具有更好的结晶度和更少的无序性.此外还得到了CIGS薄膜拉曼峰半高宽与铜含量的经验关系公式.这些研究表明拉曼光谱能比XRD更加灵敏地探测CIGS薄膜的微结构,可望作为一种无损和快速测量方法,用于对CIGS薄膜晶相和铜含量的初步估计.