Control of Defect Interactions for P-Type Doping of ZnO by Ion Implantation

这是少数职业发展奖（MCAA）项目，解决p型透明导电氧化物（TCO）和宽带隙半导体的选择性区域形成，使用离子注入，重点是ZnO作为代表材料。掺杂方法涉及在足够低的温度下进行离子注入，以冻结由离子束照射产生的晶体，从而避免产生缺陷不平衡，该缺陷不平衡妨碍了掺杂引起的晶格损伤的适当退火。低温注入之后将是样品的非常快速的原位加热，以诱导掺杂剂的短程、介电-空位复合和替代晶格位置。然后进行非原位退火以进一步退火任何残余晶格缺陷，并增强掺杂剂的电激活。通过控制缺陷的迁移率和重组，并通过仔细监测潜在的掺杂剂的晶格位置，以及注入层的电输运性质，寻求有关机制的基本信息负责的掺杂困难，通常遇到的ZnO，和其他宽带隙半导体。将对植入和退火样品的结构、成分、光学和电子输运特性进行表征。晶格无序和掺杂剂浓度作为深度的函数的测量，将执行和相关的光学和电子传输分析：卢瑟福背散射光谱法将被用来确定化学计量，作为深度的函数的组合物，和存在的杂质在薄膜中。离子通道测量将用于监测注入引起的晶格损伤，并评估掺杂剂的晶格位置（在单晶中）。离子注入物种的深度分布，以及主机衬底成分，和杂质，将与二次离子质谱研究。将通过分光光度法在透射和反射模式下分析光学特性。电子传输特性将通过霍尔效应和电导率测量来表征，作为温度的函数。该研究有望促进对ZnO和其他宽带隙半导体的电输运性质的缺陷的作用的理解，并在基于ZnO的器件的空间控制掺杂的方法的开发中。该项目解决了与具有技术相关性的电子材料相关的基础研究问题。该项目的一个重要特点是研究与教育的融合。与该项目有关的更广泛的影响体现在对本科生和研究生进行材料研究课题和方法方面的教育和培训;将研究活动中开发的材料纳入关于离子-固体相互作用的研究生/本科生课程;大力强调吸引来自代表性不足群体的学生;与拉丁美洲的团体建立科学合作;学生活动培养（研究生、大学生、高中生），如地方一级的技术研讨会和海报竞赛（佛罗里达州）;与奥兰多科学中心合作，为高中和中学科学教师举办科学讲习班;通过公布结果和在指定网站（物理系网站：www.example.com）上发布，传播科学信息www.physics.ucf.edu。

This is a Minority Career Advancement Award (MCAA) project addressing selective-area formation of p-type transparent conducting oxides (TCOs), and wide band gap semiconductors, using ion implantation, with focus on ZnO as a representative material. The doping approach involves ion implantation at a temperature low enough to freeze interstitials created by ion beam irradiation so as to avoid creation of a defect imbalance that precludes proper annealing of implantation-induced lattice damage. Low temperature implantation will be followed by a very rapid in-situ heating of the sample, to induce short range, interstitial-vacancy recombination, and substitutional lattice location of the dopants. An ex-situ annealing will then be carried out to further an-neal any residual lattice defects, and enhance electrical activation of the dopants. By controlling the mobility and recombination of defects, and by carefully monitoring the lattice location of po-tential dopants, and the electrical transport properties of the implanted layers, fundamental in-formation is sought regarding mechanisms responsible for the doping difficulties typically encountered in ZnO, and other wide band gap semiconductors. Implanted and annealed samples will be characterized for their structural, compositional, optical, and electronic transport properties. Measurements of lattice disorder and dopant concentration as a function of depth, will be performed and correlated with optical and electronic transport analyses: Rutherford backscattering spectrometry will be employed to determine stoichiometry, composition as a function of depth, and the presence of impurities in the films. Ion channeling measurements will be used to monitor implantation induced lattice damage, and to assess the lattice location of the dopants (in single crystals). The depth profiles of ion implanted species, as well as host substrate compo-nents, and impurities, will be studied with secondary ion mass spectrometry. Optical properties will be analyzed by spectrophotometry, in transmission and reflection modes. Electronic trans-port properties will be characterized by Hall effect and conductivity measurements, as a function of temperature. This research is expected to advance understanding of the role of defects on the electrical transport properties of ZnO, and other wide band gap semiconductors, and in the de-velopment of an approach for spatially controlled doping of ZnO based devices. %%% The project addresses fundamental research issues associated with electronic materials having technological relevance. An important feature of the project is the integration of research and education. Broader impacts associated with the project are exemplified by education and training of undergraduate and graduate students in materials research topics and methodologies; incorporation of the materials developed in the research activity in a graduate/undergraduate class on ion-solid interactions; a strong emphasis on attracting students from underrepresented groups; establishment of scientific collaborations with groups from Latin America; fostering of activities for students (graduate, undergraduate, high school) such as technical symposia and poster session competitions at the local level (Florida State); development of science workshops for high and middle school science teachers in collaboration with Orlando Science Center; and dissemination of scientific information by publishing the results, and posting on a designated website (within the Physics Department website: www.physics.ucf.edu).