溅射制备Zn(O,S)薄膜及其在CIGS电池中的应用

通过射频磁控溅射(MS)工艺,在不同溅射功率下制备Zn(O,S)薄膜,并将其应用于CIGS异质结器件结构中.采用XRD、XRF、台阶仪、透反射光谱仪、SEM以及wxAMPS仿真软件对Zn(O,S)薄膜以及MS-Zn(O,S)/CIGS异质结器件进行研究.结果表明,低功率条件下(<80 W),Zn(O,S)薄膜内S/Zn明显降低,带隙减小,所制备的微晶或非晶结构Zn(O,S)薄膜材料中生成闪锌矿结构ZnS (α-ZnS);高溅射功率下(>100 W),薄膜内S/Zn增加并趋于稳定,Zn(O,S)材料结晶性能改善,α-ZnS消失,带隙增加.器件仿真结果表明,低功率条件下,缓冲层与吸收层(AB)界面导带失调值(CBO)增大,空间电荷区(SCR)复合加剧;高功率条件下,器件品质因子升高明显,主要是由于高功率引起的异质结界面类受主缺陷浓度增加.

Preparation of Zn(O,S) Thin Films with Magnetron Sputtering Method and Application in CIGS Solar Cell

Different Zn(O,S) thin films were prepared with various magnetron sputtering (MS) power and applied to the CIGS heterojunction solar cell, the Zn(O,S) thin films were investigated by XRD, XRF, profilometer, ultraviolet-visible-near infrared spectrophotometer, moreover, the analysis of MS-Zn(O,S)/CIGS heterojunction devices were completed by scanning electron microscope and wxAMPS simulation software.The results show that, the sulfur content within Zn(O,S) thin film and the optical band gap decreases significantly with lower sputtering power (<80 W).Meanwhile, α-ZnS generated in the amorphous or nano-crystalline Zn(O,S) thin film.With a higher sputtering power (>100 W), the sulfur content and optical band gap will increase and then become stable, moreover, α-ZnS can be removed within significant increased crystallization of Zn(O,S) thin film.According to the simulated results, the degradation of MS-Zn(O,S)/CIGS devices prepared under lower sputtering power (<80 W) are due to high offset between buffer layer and absorber layer which can lead to high recombination in SCR, while the degradation of the devices prepared under higher sputtering power (>100 W) are due to the high acceptor-like defect density at the interface of MS-Zn(O,S)/CIGS heterojunction which is induced by plasma bombing with higher sputtering power.