Carrier Doping in Epitaxial (Zn,Mg)O Thin Films

外延 (Zn,Mg)O 薄膜中的载流子掺杂

• 批准号: 0305228
• 负责人: David Norton
• 金额: $ 35万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-15 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0305228&HistoricalAwards=false
• 关键词: Carrier; Doping; Epitaxial; Zn; Mg

This project addresses controlled n-type and p-type doping of (Zn,Mg)O for wide bandgap elec-tronics. The approach includes the synthesis and properties of carrier-doped (Zn,Mg)O crystalline thin films with a focus on understanding the formation of acceptor and donor states in epitaxial (Zn,Mg)O thin films. The alloy compositions of interest include the Zn-rich region for which the phase-pure wurtzite structure can be realized, as well as the Mg-rich region where the rock-salt structure is obtained. The objective is to understand the role of dopant species, complex forma-tion, and growth conditions on the incorporation of activated dopants. Activities will include the study of doping using two complementary epitaxial film-growth techniques. First, anion doping with group V acceptors (primarily N) will be investigated using molecular beam epitaxy. Specific theoretical predictions have been made regarding the effectiveness of single nitrogen versus multi-nitrogen bearing molecules as the delivery species for nitrogen doping. The role of Zn in-terstitials, oxygen vacancies, and/or hydrogen complexes in forming compensating shallow donor levels imposes the need to simultaneously consider the role of in situ and post-growth processing conditions. Second, pulsed-laser deposition will be used to investigate both acceptor doping and donor doping of (Zn,Mg)O. The donor dopant will be a group III element (Ga) substituted on the cation site. For acceptor doping using pulsed laser deposition, the primary focus will be on phos-phorus doping, as recent results suggest p-type behavior in heavily P-doped ZnO surfaces. It has also been predicted that co-doping with certain donor impurities may lead to a lowering of the acceptor levels due to the formation of acceptor-donor-acceptor complexes. As a secondary op-tion to p-type doping, co-doping approaches will be considered, with the focus on determining whether deep acceptor levels can be shifted to lower energies via the formation of acceptor-donor-acceptor complexes. Temperature-dependent Hall, Seebeck, C-V, and resistivity meas-urements will be used to determine conduction mechanisms, carrier type, and doping. Low tem-perature photoluminescence and admittance spectroscopy will be used to determine the location of the acceptor level for a given dopant. X-ray diffraction will used to characterize film crystal-linity. .%%% This project addresses basic research issues in a topical area of materials science with significant technological relevance, and places emphasis on the integration of research and education. Pro-ject activities will include developing a tutorial on Electronic Oxide Physics and Materials to be delivered as part of the Graduate Student Seminar Series in both Materials Science and Physics. It will be presented on an annual basis either by the PI or the graduate students involved in the re-search. The presentation materials will be posted on a designated website, thus providing access for researchers and students outside the University of Florida. In order to enhance the exposure of undergraduate students to oxide electronics, and research in general, the research project will in-corporate undergraduates through an existing Senior Research Thesis program. Each year, a fourth-year Materials Science and Engineering undergraduate student will be recruited to select an oxide electronics-related project as his or her Senior Thesis research topic. Persons from un-der-represented groups (women, minorities) will be particularly encouraged to participate.***

本项目研究用于宽禁带电子学的可控n型和p型掺杂(锌，镁)O。该方法包括载流子掺杂(锌，镁)O晶体薄膜的制备和性质，重点是了解(锌，镁)O外延薄膜中受主和施主状态的形成。感兴趣的合金成分包括可实现相纯纤锌矿结构的富锌区和获得岩盐结构的富镁区。目的是了解掺杂剂种类、络合物形成和生长条件对活性掺杂剂掺入的影响。活动将包括使用两种互补的外延薄膜生长技术研究掺杂。首先，将利用分子束外延技术研究V族受体(主要是N)的阴离子掺杂。对于单氮和多氮分子作为氮掺杂的输送物种的有效性，已经做出了具体的理论预测。锌离子、氧空位和/或氢络合物在形成补偿的浅施主能级方面的作用要求同时考虑原位和生长后处理条件的作用。其次，用脉冲激光沉积的方法研究了(Zn，Mg)O的受主掺杂和施主掺杂。施主掺杂将是阳离子位置上取代的III族元素(Ga)。对于使用脉冲激光沉积的受主掺杂，主要的焦点将是磷掺杂，因为最近的结果表明，重磷掺杂的氧化锌表面具有p型行为。也有人预测，与某些施主杂质共掺杂可能会由于形成受主-施主-受主络合物而导致受主能级的降低。作为p型掺杂的次要操作，将考虑共掺杂方法，重点是确定是否可以通过形成受主-施主-受主复合体来确定深受主能级是否可以向较低的能量移动。温度相关的霍尔、塞贝克、C-V和电阻率测量将被用来确定导电机制、载流子类型和掺杂。低温光致发光和导纳光谱将被用来确定特定掺杂剂的受主能级位置。X射线衍射法将用来表征薄膜的晶型。这个项目解决了材料科学中一个具有重大技术意义的专题领域的基础研究问题，并强调研究和教育的结合。项目活动将包括编写关于电子氧化物物理和材料的教程，作为材料科学和物理学研究生研讨会系列的一部分。它将每年由私人侦查员或参与研究的研究生提交。演示材料将张贴在指定的网站上，从而为佛罗里达大学以外的研究人员和学生提供访问权限。为了加强本科生对氧化物电子和一般研究的接触，该研究项目将通过现有的高级研究论文计划在企业本科生中进行。每年将招收一名材料科学与工程专业的四年级本科生，选择一个与氧化物电子相关的项目作为他或她的高级论文研究课题。将特别鼓励具有代表性的群体(妇女、少数群体)的人员参加。*