稀土半导体Cu(In,R)Te_2(R=稀土)的结构和拉曼散射研究

Structures and Raman Scattering Study of Rare Earth Doped Cu( In,R)Te_2(R= Rare Earth) Semiconductors

利用稀土元素独特的光、电特性,成功地制备出稀土掺杂的CuIn1-xRxTe2(R=稀土)(CIRT)新型光伏半导体材料。应用X射线衍射、扫描电镜、拉曼散射等进行了相关的晶体结构、显微组织、光性能研究。研究表明:稀土元素的掺杂能够稳定黄铜矿型的晶体结构,点阵常数随稀土元素的掺杂呈现出涨落性。应用Rietveld方法测定原子占位,稀土元素部分替代In占据4b晶位。稀土元素的掺杂导致晶粒团聚现象,并形成柱状或层状单晶颗粒,具有透光性。CuInTe2和CuIn0.9Sm0.1Te2的Eg值分别为1.25和1.32 eV,这表明:CuIn0.9Sm0.1Te2与CuIn1-xGaxTe2具有接近的禁带宽度,适宜做光伏材料。拉曼散射实验证实:稀土元素的添加对于光散射诱发的原子振动频率有较大的影响,使得一些原有频率消失,有助于光谱频段的选择性吸收。

Based on many special luminescence and photo-voltage characteristics of rare earth elements,we designed some novel rare earth doped CuIn1-xRxTe2（ R = rare earth） photo-voltage semiconducting materials. Their crystal line structures,microstructures and optical properties were investigated with X-ray diffraction,scan electron microscopy and Raman scattering. It showed that the rare earth elements stabilized the chalcopyrite structure,and induced the lattice fluctuation. Based on the Rietveld method,rare earth element substitution for indium occupies4 b crystal position. SEM showed rare earth doping in CuIn1-xRxTe2 induces grain agglomeration phenomenon and forms some column-like or flake-like single crystals with light-transmission. The band gap Egvalues before and after0. 1 mol Sm doped into CuInTe2 were 1. 25 and 1. 32 e V,respectively. Sm doped into CuInTe2 shows CuIn0. 9Sm0. 1Te2 has a close forbidden band width with CuIn1-xGaxTe2 and it is suitable for photovoltaic materials. The Raman scattering measurement proved that the rare earth significantly affects the atom vibrating,and result in the losses of vibrating peaks. It revealed that the rare earth doping into CuIn1-xRxTe2 is helpful for the absorptions of spectra with special frequencies.