Cu掺杂提高类金刚石膜场致发射特性研究

Enhancement of Field Emission Characteristics of Diamond-Like Carbon Films by Cu Doping

采用双磁过滤阴极真空弧和磁控溅射沉积法,在Cu基体表面上制备了以钛(Ti)和钛化碳(TiC)过渡层材料的Cu掺杂非晶类金刚石(DLC)薄膜。自行设计制作了薄膜材料场致发射特性测试装置,探讨了Cu掺杂影响DLC薄膜场致发射特性的机理。运用扫描电子显微镜(SEM)和拉曼光谱分析了铜掺杂DLC薄膜的微观结构组成和表面形貌的变化。研究发现,相对于未掺杂的DLC膜,掺Cu DLC膜具有更好的场致发射特性,开启电压从45降为40 V/μm。SEM分析显示适当的Cu掺杂可使薄膜表面具有更加精细的亚微米级突起结构,突起之间连接更加紧密。Raman分析结果显示:适当的Cu掺杂可以使薄膜中的sp^(2)杂化键含量和薄膜的导电性提高,场致发射特性更好;过度掺杂Cu则会使薄膜表面含有过多Cu而致场致发射特性下降。

The Cu-doped diamond-like-carbon(DLC)films were deposited on the Cu-substrate,coated with TiC/Ti transition layers,in the self-developed coating reactor.The influence of the Cu-doping on the field emission characteristics and microstructures was investigated with scanning electron microscopy and Raman spectroscopy.The preliminary results show that Cu-doping had a major impact.To be specific,as the Cu-content increased,the density of irregularly shaped"sub-micro cusp"changed in an increase-decrease-vanish mode,and the conductivity of Cu-doped DLC coating increased because of the increase of sp^(2) and Cu surface densities,bringing about an enhancement-deterioration of the field emission behavior.For example,the optimized Cu-doping decreased the emission onset field to 40 V/μm,5 V/μm lower than that of the undoped DLC-sample.However,an over-doping of Cu deteriorated the field emission properties.