溶胶-凝胶法制备Co,Cu共掺杂ZnO薄膜 结构及光学特性

采用溶胶-凝胶法在玻璃基片上制备了纯ZnO薄膜和高浓度Cu掺杂的Co,Cu共掺ZnO(Zn0.90CoxCu0.1-xO,x=0.01,0.03,0.05)薄膜。扫描电镜观察到无论是纯ZnO还是掺杂ZnO薄膜表面都有均匀分布的颗粒,但是在Cu含量较高时均匀性更好。X射线衍射揭示所有样品都具有纤锌矿结构,但是Cu掺杂量的增加使晶格常数略有减小,而晶粒尺寸却略有增大。XPS测试结果表明样品中Co离子的价态为+2价和+3价,Cu离子的价态为+2价和+1价共存。室温光致发光测量在所有样品中均观察到较强的紫外发光峰、蓝光双峰和较弱的绿光发光峰。

Structure and Optical Properties of (Co,Cu)-codoped ZnO Thin Films Prepared by Sol-gel Method

Undoped ZnO films and (Co,Cu)-codoped ZnO (Zn_0.90Co_{xCu0.1-xO, x = 0.01, 0.03, 0.05) thin films were fabricated on glass substrates by sol-gel method. SEM reveals that there are uniform nanoparticles on the surfaces of pure and (Co, Cu)-codoped ZnO thin films, but better uniformity is achieved for higher Cu concentration. The XRD results reveal preferential orientation along the (002) direction for all ZnO samples. With the increase of Cu concentration, the lattice constant of doped films slightly decrease but the crystal grain size slightly increases. XPS results reveal the existence of Co²⁺ and Co³⁺ for Co, Cu²⁺ and Cu⁺ for Cu. The increase in the amount of doping Cu, accompanied by an increase of Cu²⁺ and Cu⁺ concentration, leads to an increaseof zinc vacancy and zinc interstitial. As such, strong ultraviolet emission peaks, blue double emission peaks and weak green emission peaks are observed in the photoluminescence spectra of all samples at room temperature.}