Na-Mg共掺杂ZnO薄膜的结构和光学性质

利用溶胶-凝胶法,在普通载玻片上使用旋转涂膜技术制备了具有c轴择优取向生长的Na-Mg共掺杂的ZnO薄膜。用XRD、SEM、光致发光(PL)及透射光谱对薄膜样品进行了表征。结果表明:Na-Mg共掺杂有利于ZnO薄膜的c轴择优取向生长,并且随着Na+掺杂浓度的增加,晶粒尺寸先增大后减小;通过比较不同掺杂浓度ZnO薄膜的PL谱,推测发光峰值位于380nm的紫外发射与ZnO的自由激子复合有关;发现掺入Mg的确能使ZnO禁带宽度增大,掺杂组分为Na0.04Mg0.2Zn0.76O时,其PL谱只有一个很强的紫光发射峰,其近带边紫外光发射强度较未掺杂的ZnO增强了近10倍,极大地提高了薄膜紫外发光性能;并且随Na+浓度增加薄膜透光性减弱。

Structural and Optical Properties of Na-Mg Co-doped ZnO Film

The Na-Mg co-doped hexagonal wurtzite thin ZnO film with the c-axis (002) preferred orientation were fabricated on lime-glass substrate by sol-gel spin coating method. The phase structural characteristics and surface morphology as well as optical properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL) and transmittance, respectively. The results showed that Na-Mg co-doping is propitious to the ZnO film growth along the c-axis .The crystal size is influenced by the increase amount of Na content. Proved the ultraviolet emission peak at 380 nm is from the recombination luminescence for exciton energy levels, and found that Mg doped ZnO can make band gap increase indeed. The PL spectrum of Na0.04Mg0.2Zn0.76O has only one violet emission peak, and the transmittance and the band-gap of the Na-Mg co-doped ZnO films are decreased with the increasing of Na content.