衬底温度对电子束反应蒸发生长的ZnxCo1-xO薄膜性能的影响  

Influence of substrate temperature on the characteristics of reactive e-beam evaporated ZnxCo1-xO films

作　　者：刘谱成[1] 邱东江[1] 施红军[2] 蒋银土[3] 顾智企[1] 吴惠桢[1] 

机构地区：[1]浙江大学物理系,浙江杭州310027 [2]浙江大学信息与电子工程学系,浙江杭州310027 [3]浙江大学化学系,浙江杭州310028

出　　处：《功能材料》2007年第A03期1014-1017,共4页Journal of Functional Materials

基　　金：国家自然科学基金资助项目（50472058）.

摘　　要：采用电子束反应蒸发法生长ZnxCo1-xO薄膜。通过X射线衍射、场发射扫描电子显微镜、光致荧光光谱（PL）、室温M-H曲线等测量研究衬底温度对Zn0∞C00-250薄膜微结构及光学、磁学特性的影响。结果表明，250～350℃温度范围内生长的Zn0.75Co0.25O薄膜具有单一的纤锌矿结构，但当温度超过400℃时产生CoO杂相偏析。在300或350℃衬底温度下生长Zn0.75Co0.25O薄膜具有室温铁磁性，PL测量结果表明Zn0.75Co0.25O薄膜的室温铁磁性很可能起源于氧空位缺陷诱导的自旋劈裂杂质带机制．而250℃生长Zn0.75Co0.25O薄膜在室温下呈现超顺磁性，超顺磁性的产生是Zn0.75Co0.25O晶粒的小尺寸效应所导致。Zn0.75Co0.25O films were fabricated via reactive electron beam evaporation. The impact of substrate temperature on the structural, optical and magnetic properties of Zn0.75Co0.25O films was investigated by X-ray diffraction, field emission scanning electron microscope, photoluminescence （PL） and field dependent DC magnetization measurements. It is shown that wurtzite structured homogeneous Zno.Zn0.75Co0.25O films can be obtained at low temperatures in the range 250～350℃. However, inhomogeneous ZnxCo1-xO films were obtained when the temperature is enhanced to 400℃.. Films synthesized at 300 or 350 ℃ reveal room temperature （RT） ferromagnetism, but 250 ℃ fabricated Zn0.75Co0.25O film shows superparamagnetism at RT. PL investigations favor the O-vacancy induced spin-split impurity band mechanism for comprehending RT ferromagnetism of homogeneous Zn0.75Co0.25O films grown at 300 or 350℃. While the superparamagnetism of 250Zn0.75Co0.25O synthesized Zn0.75Co0.25O film is due to the small size effect of nanoparticles in the film.

关 键 词：Zn0.75Co0.25O薄膜 微结构 光学特性 磁特性 

分 类 号：O472[理学—半导体物理]