不同含量Cd掺杂对Cu_2SnS_3薄膜结构和性能的影响

Effects of Different Cd Doping on the Structures and Properties of Cu_2SnS_3 Thin Films

通过溶液法合成了Cu_2SnS_3(CTS)薄膜,并研究了不同Cd含量对CTS薄膜晶体结构和性能等方面的影响.研究发现通过Cd掺杂可以有效调节CTS的光学带隙(Eg).不添加Cd时,样品为面心立方相的CTS(C-CTS),带隙为0.82 eV.当Cd含量在4.18%~13.38%的范围内时,立方相的CTS逐渐转变为立方结构固溶体(C-CTS:Cd)和四方结构固溶体(T-CTS:Cd).通过改变制备样品的Cd掺杂含量,可实现带隙从0.82~1.26 eV的调节.XPS测试结果表明,CTS(即未掺杂Cd的CTS)样品中,Cu、Sn和S元素的价态分别为+1,+4和-2价.SEM形貌结果显示所有的Cu-Sn-S-Cd(CTSC)合金薄膜都表现出光滑和紧凑的表面形态并没有观察到明显的孔或裂纹.所制备的单一相的C-CTS和T-CTS:Cd薄膜可以作为太阳能电池的吸收层材料.

We fabricated solid solution of Cd in the Cu2SnS3（ CTS： Cd） thin film by Cd doping in the Cu2SnS3（ CTS） with a simple solution approach,and investigated the effects of Cd content on crystalline structure and bandgap（Eg）. It was found that a face-centered cubic CTS（ C-CTS） film with Eg of 0. 82 eV can be prepared by the solution approach. The C-CTS transformed into CTS： Cd with cubic structures（ C-CTS： Cd） tetragonal structures（ T-CTS： Cd） when the Cd contents is in the range of 4. 18% ~ 13. 38%. The Egcan be tuned from0. 82 ~ 1. 26 eV by changing the Cd doping content for the CTSC samples. XPS results suggest that the valence states of Cu,Sn and S ions for the CTSC（0） film are ＋ 1,＋ 4,and -2,respectively. SEM results shown that all the CTSC alloy thin films show the smooth and compact surface morphologies and no obvious holes or cracks can be observed. It is believed that the single phase of C-CTS and T-CTS： Cd films will be promising absorber materials of solar cells.