N掺杂Mg_xZn_(1-x)O薄膜结构和光学性质研究

Study on Crystal Structures and Optical Properties of Mg_xZn_(1-x)O∶N Thin Films

采用溶胶-凝胶法在玻璃衬底上制备了N掺杂Mg_xZn_(1-x)O薄膜。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射光谱、光致发光(PL)谱对N掺杂Mg_xZn_(1-x)O薄膜样品的晶体结构、表面形貌和光学性能进行了研究。XRD结果表明所有样品均形成了Mg Zn O合金薄膜,没有观察到其它氧化物的衍射峰。样品的结晶质量越差,样品的表面形貌越不规则,但样品在可见光的透射率越强,甚至达到了95%。样品的禁带宽度随Mg含量的增加而增加,随N含量的增加而减小。所有样品的光致发光谱均观察到强的400 nm发光和弱的可见发光。400 nm的发光强度随Mg含量的增加而减弱,随N含量的增加而增强,认为薄膜在400 nm的发光来源Zn O的激子复合。

The Mg_xZn_（1-x）O ∶ N thin films are fabricated on the glass substrates by sol-gel method.The surface morphologies,crystal structures and optical properties of the films were investigated by scanning electron microscopy（SEM）,X-ray diffraction（XRD）,transmission spectrum and photoluminescence（PL） spectrum.The XRD results reveal that all the Zn O films are of wurtzite structure.The diffraction peaks of other oxide are not observed in the samples.The crystal quality was lowers,the surface topography of the Zn O films is irregular,but the transmittance in the visible region is increases,and even reaches 95%.The optical band gap increases with the Mg concentration increasing,and decreases with the increase of N concentration.The stronger UV（400 nm） emission and the weaker visible emission peaks are observe in the PL spectra of all the samples.With the increase of N concentration,the UV emission peak enhanced first,and then the UV peak was weakened again,that the UV emissions at 400 nm are attributed to recombination of free excitons in Zn O.