稀土元素(Gd,Y)掺杂CdS薄膜的制备及其性能研究

PREPERATION AND PERFORMANCE STUDY OF Cd S THIN FILM DOPED BY RARE EARTH ELEMENT(Gd,Y)

采用化学水浴法两次沉积CdS,结合电子束真空蒸发法在两层CdS之间引入稀土层,制备含有不同厚度稀土Gd、Y掺杂层的CdS多晶薄膜。利用XRD、SEM、EDX、UV-VIS透射光谱和霍尔效应测试仪对薄膜的晶型、表面形貌、化学组成、光学及电学性能进行研究。结果表明:未掺杂的薄膜为沿(111)晶面择优生长的立方相闪锌矿结构,导电类型为n型。含有稀土Gd(Y)掺杂层的CdS多晶薄膜为立方相和六方相的混合结构,导电类型仍为n型,薄膜的均匀性和致密性得到改善,薄膜中Cd和S的原子比更接近CdS的化学计量比,稀土掺杂可提高CdS薄膜在可见光范围内的透过率,使薄膜载流子浓度增大、导电性能明显增强。

Two layers of pure CdS thin films were twice deposited by chemical bath deposition （CBD）. The introduction of rare earth layer between two layers of CdS was deposited by the electron beam evaporation method, then CdS/Gd（Y）/ CdS muhilayer films with different thickness rare earth Gd （Y） layer were prepared. The structure, superficial topography, component, optical and electrical properties of the CdS samples were characterized by XRD, SEM, EDX, UV-VIS and Hall Effect measurements. The results show that pure CdS thin films are cubic blende structure and preferentially orient in （111 ）directions. Its conductive type is n type. CdS thin films doped by rare earth element Gd （Y） are a mixed structure of cubic and hexagonal phase, and the conductive type is still n type. The uniformity and compactness of the films are improved. At the same time, the proportion of Cd and S atoms in films doped by rare earth element are more close to the stoichiometric ratio of CdS. Rare earth doping can also make the transmittance in the visible region increase and result in an obvious improvement of the electrical properties, such as lower resistivity and higher carrier concentration.