论文标题:氧化锌薄膜电学特性的研究
The Electrical Properties of ZnO Thin Films
论文作者
论文导师 刘益春,论文学位 硕士,论文专业 理论物理
论文单位 东北师范大学,点击次数 103,论文页数 42页File Size985k
2006-06-01论文网 http://www.lw23.com/lunwen_794753592/
ZnO;p-type;n-type;Hall effect
由于紫外波段激光器在信息显示和信息存储特别是在海底探测,紫外通讯和光存储,医疗和诊断,防伪和检测,分析仪器等方面都有十分重要的应用,是一项具有重要应用前景的基础研究。氧化锌作为一种宽带隙半导体(3.3eV),激子束缚能大(60meV),在室温下容易获得强的激子发射,而且可能成为紫外激光的重要材料。因此,对氧化锌的研究已成为继GaN之后宽带隙半导体研究的又一热点。为了获得高质量的氧化锌薄膜材料,人们已采用分子束外延,有机化学汽相沉积,脉冲激光沉积,磁控溅射等各种技术来制备氧化锌薄膜材料。尽管,自从2004年日本、中国和美国的科学家先后获得了ZnO半导体二极管的电致发光,然而,由于缺少质量更高的n型和更稳定的p型ZnO薄膜,ZnO基的半导体激光器,还很难实现。本论文针对这些困难开展了以下方面的研究:1.研究了由P-MBE制备的未掺杂的ZnO薄膜,通过测试霍尔效应发现在650℃生长温度下有最好的电学特性;同时,研究了N掺杂的ZnO薄膜,发现在低温与富锌条件下生长,出现了类金属导电。2.讨论了p型ZnO薄膜的不稳定性。发现当p型ZnO薄膜被光子能量大于2.76eV的蓝光辐照后,转变成n型,我们初步认为是由于深能级缺陷中的电子被激发导致的。3.在p型ZnO薄膜制备了金电极,铟电极和镍/金合金电极,对比不同的退火条件,发现镍/金合金电极具有较好的欧姆接触。
Recently much attention has been paid to short wavelength lasers for use in highdensity information storage, information display, UV communication, medicaltreament & diagnisis, and so on, which make it become an important basal researchwith extensive application. It is widely accepted that ZnO is one of the mostpromising materials for producing an ultraviolet laser at room temperature due to itswide direct band gap (Eg=3.3eV) and large excitonic binding energy of 60 meV,which was testified by the results of optically pumped stimulated emission and lasingfrom ZnO thin films. Like GaN compound, the reasearch about ZnO has burned whitehot in the range of wide band gap. Japanese scientists, Chinese scientists andAmerican scientists have fabricated LED based on ZnO film, however, developmentof LD has been limited by the lack of the higher qulity n-type and reliable p-typeZnO.. According to the present research hotspots and difficulties on ZnO, weinverstigated the electric properties of ZnO thin films. The details are as follow:1. Investigated undoped ZnO thin films which were prepared by P-MBE .Found thatthe ZnO thin films posses the best electric properties prepared at 650℃ by halleffect. . N-doped Zinc oxide Metal condution behavior emerged, when ZnOthin films have grown on c-Al2O3 substrate in Zn-rich conduction andlow substrate temperature.2. The reasons for unstable p-type ZnO were discussed. The p-type ZnO thin filmconverts to n-type after illumination by blue light of photon energy over than 2.67eV. Considering the effect of nonequilibrium n-type conduction in p-type ZnO, adeeper level trap states model was supposed.3. Prepared Au, In and Ni/Au contacts on p-type ZnO thin films. Compared differentannealing conditions, found Ni/Au contact gives a better ohmic characteristic
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