Photoluminescence study of cadmium zinc telluride
Photoluminescence study of cadmium zinc telluride
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DOI：
10.33915/etd.1252
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发表时间：
2001
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影响因子：
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通讯作者：
Swati Jain
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文献类型：
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作者：
Swati Jain
本文利用光致发光（PL）技术对0≤x≤0.14的cd1 - xznxte晶体进行了详细的研究。本文特别介绍了我在研究过程中进行的几个实验，目的是：1)识别大块CdZnTe （CZT）晶体中各种点缺陷特征的各种辐射跃迁，2)确定这些晶体中的锌浓度，3)识别室温PL的性质。我在液氦温度下对各种掺杂和未掺杂的CdZnTe晶体进行了PL光谱，并获得了低温下的自由激子能量和带隙。然后我用文献中提出的各种表达式来评估锌的浓度。我对11种不同锌浓度的样品（掺杂和未掺杂）进行了详细的PL研究，作为温度的函数，以验证用于辐射探测器/红外衬底应用的CZT生长的室温PL的来源。PL测量是在5 ~ 300 K的温度范围内进行的。目前大块CZT生长的趋势可以产生稍微n型的材料（希望具有高电阻率或高补偿材料）。在目前为辐射探测器生长的最先进的CZT中，通常观察到以供体束缚激子发射为主的5-K PL光谱（D， X）。此外，通常可以检测到与Cd空位相关的复合物相关的深受体结合激子（a， X）。因此，进行一项研究并确定大量CZT生长的“新”趋势是否会对300-K pl的起源产生不同的结论是很有兴趣的。iii致谢我想对我的导师Nancy C. Giles博士表示衷心的感谢和深刻的感谢，她不仅给了我与她一起在各种项目上工作的机会，而且把我介绍给了光致发光光谱这个令人兴奋的领域。我很感激她给了我这么多的时间，并在实验室及其操作的各个方面教育我，无论是关于设备的知识，他们的安全或操作。她愿意在任何时候帮助任何事情，我都非常感激。在她的亲切指导、宝贵支持、耐心、浓厚的兴趣、贡献和发人深省的见解下，我完成了这项工作，并学会了成为一名更好的实验学家和物理学家。我要感谢Larry Halliburton博士，在过去两年的研究生学习中，他对我的友善、耐心、有启发的建议和鼓励，以及他在我的委员会任职。我要感谢Mohindar S. Seehra博士在整个研究过程中就固体物理理论和实验的各个方面所做的宝贵和令人振奋的演讲，以及他是我的监护人。我也感谢他在我的委员会任职。我要感谢技术人员：卡尔·韦伯、道格·马瑟斯、汤姆·米拉姆和查克·西奇纳，感谢他们在需要的时候帮助我修理和制作设备。我还要感谢系里的所有成员，教职员工，尤其是Sherry Puskar和Siobhan Byrne，他们在行政细节方面帮助了我。
PHOTOLUMINESCENCE STUDY OF CADMIUM ZINC TELLURIDE SWATI JAIN In this thesis, I present a detailed study of Cd 1-xZnxTe crystals with 0 ≤ x ≤ 0.14 using photoluminescence (PL) spectroscopy. This thesis describes in particular several of the experiments performed during the course of my study with the purpose of: 1) identifying various radiative transitions that are signatures of various point defects in bulk CdZnTe (CZT) crystals, 2) determining the zinc concentration in these crystals, and 3) identifying the nature of room-temperature PL. I took PL spectra at liquid helium temperatures for various doped and undoped CdZnTe crystals and obtained the free exciton energy and hence their bandgaps at low temperatures. Then I used the various expressions proposed in the literature to evaluate the zinc concentrations. I have performed a detailed PL study on eleven different samples having different zinc concentrations, doped and undoped, as a function of temperature to verify the origin of the room-temperature PL from CZT grown for radiation detector/IR substrate applications. The PL measurements were made in the temperature range from 5 K to 300 K. The current trend in the bulk CZT growth produces material that can be slightly n-type (it is desirable to have high resistivity, or highly compensated material). In the current state-of-theart CZT grown for radiation detectors, it is common to observe 5-K PL spectra dominated by donor-bound exciton emission (D , X). Also, a deep acceptor-bound exciton (A , X) related to a complex associated with Cd vacancies is usually detected. Thus, it was of interest to perform a study and determine whether the “new” trend in bulk CZT growth would produce a different conclusion about the origin of the 300-K PL. iii ACKNOWLEDGEMENTS I would like to express my heartfelt thanks and profound gratitude to Dr. Nancy C. Giles, my advisor, for not just giving me the opportunity to work with her on various projects but introducing me to this exciting field of Photoluminescence Spectroscopy. I am indebted to her for giving me so much of her time and educating me in various aspects of lab and its operation whether it is regarding knowledge of equipment, their safety or operating them. Her willingness to help with anything at any time is greatly appreciated. Under her kind guidance, invaluable support, patience, keen interest, contributions and stimulating insight throughout the course of this study, I was able to complete this work and learned to become a better experimentalist and physicist. I am grateful to Dr. Larry Halliburton for his kindness, patience, inspired suggestions, and encouragement over the past two years of my graduate studies in the department and in the lab and for serving on my committee. I am thankful to Dr. Mohindar S. Seehra for his invaluable and stimulating lectures on various aspects of theoretical and experimental Solid State Physics throughout the course of this study and for being my guardian away from home. I also thank him for serving on my committee. I am thankful to the technical staff: Carl Weber, Doug Mathess, Tom Milam, and Chuck Sicina for their help in fixing and making equipment whenever needed. I would also like to thank all members of the department, faculty and staff, especially Sherry Puskar and Siobhan Byrne for helping me with the administrative details.