• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Thermodynamic analysis and determination of spontaneous emission quantum efficiency for luminescence refrigeration in semiconductors.
【24h】

Thermodynamic analysis and determination of spontaneous emission quantum efficiency for luminescence refrigeration in semiconductors.

机译：半导体发光制冷的自发发射量子效率的热力学分析和确定。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Luminescence refrigeration in semiconductors has recently attracted much interest and has developed into an active area of research. This dissertation focuses on understanding the fundamental mechanisms of luminescence refrigeration. To fulfill this task, the thermodynamic principles of luminescence refrigeration in semiconductors are investigated based on the balance equations for energy, entropy, and particle number. By taking background radiation into account, the output and input fluxes are examined using a thin-slab model in the steady state, through which the cooling efficiency and cooling power are obtained. The concept of radiation flux temperature is clarified and the origination of irreversible entropy generation during luminescence is investigated. The Eddington factor is also discussed.; High material quality is critical to the achievement of net cooling in luminescence refrigerators. To this end photoluminescence spectroscopy is utilized to characterize molecular beam epitaxy (MBE) grown samples; this information is then fed back to the growth of GaAs based luminescent devices to ensure the highest quality materials. The impact of Sb mediated growth on the performance of GaAs/AlGaAs materials is also studied. Moreover, the MBE system is precisely calibrated to ensure the accurate growth of device structures. The MBE calibration procedures using reflectance measurements and the growth rate calibration curves versus cell temperature for GaAs, AlAs, and InAs, the As/III overpressure versus As cell valve setting, and the dopant concentrations versus dopant cell temperatures are also presented.; Spontaneous emission quantum efficiency is one of the most important parameters in luminescence refrigeration. The injection and temperature dependence of the spontaneous emission quantum efficiency in GaAs/AlGaAs heterostructures and InGaAs/GaAs quantum wells is studied using photoluminescence measurements performed at temperatures from 50 to 320 K using a HeNe pump laser with power ranging from 0.6 to 35 mW. The quantum efficiency is inferred from the power law relations predicted by the rate equations that link pump power and integrated photoluminescence signal. For the GaAs/AlGaAs heterostructures, the use of Sb mediated growth improved the extrapolated peak spontaneous emission quantum efficiency from 0.970 to 0.977 at 300 K, with the best overall performance from 0.996 to 0.998 at 180 K. For the InGaAs/GaAs quantum well structure, the extrapolated peak spontaneous emission quantum efficiency is 0.941 at 300 K, with a best overall performance of 0.992 at 100 K.
机译：半导体中的发光制冷最近引起了人们的极大兴趣，并已发展成为一个活跃的研究领域。本文主要研究发光制冷的基本机理。为了完成这一任务，基于能量，熵和粒子数的平衡方程，研究了半导体发光制冷的热力学原理。通过考虑背景辐射，在稳态下使用薄板模型检查了输出和输入通量，从而获得了冷却效率和冷却功率。阐明了辐射通量温度的概念，并研究了发光过程中不可逆熵的产生。还讨论了爱丁顿因子。高质量的材料对于实现发光冰箱的净冷却至关重要。为此，利用光致发光光谱来表征分子束外延（MBE）生长的样品。然后，这些信息将反馈到基于GaAs的发光器件的增长，以确保获得最高质量的材料。还研究了Sb介导的生长对GaAs / AlGaAs材料性能的影响。此外，MBE系统经过精确校准，以确保器件结构的精确增长。还给出了使用反射率测量和生长速率校准曲线对GaAs，AlAs和InAs的电池温度，As / III超压与As电池阀设置以及掺杂剂浓度与掺杂剂电池温度的MBE校准程序。自发发射量子效率是发光制冷中最重要的参数之一。使用HeNe泵浦激光器在50至320 K的温度下使用功率为0.6至35 mW的HeNe泵浦进行光致发光测量，研究了GaAs / AlGaAs异质结构和InGaAs / GaAs量子阱中自发发射量子效率的注入和温度依赖性。量子效率是由将泵浦功率与积分光致发光信号联系起来的速率方程式所预测的幂律关系来推断的。对于GaAs / AlGaAs异质结构，使用Sb介导的生长可以将300 K时的外推峰值自发发射量子效率从0.970提高到0.977，在180 K时具有最佳的整体性能，从0.996到0.998。InGaAs / GaAs量子阱结构，外推峰自发发射量子效率在300 K时为0.941，在100 K时的最佳整体性能为0.992。

著录项

  • 作者

    Ding, Ding.;

  • 作者单位

    Arizona State University.;

  • 授予单位 Arizona State University.;
  • 学科 Physics Radiation.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 104 p.
  • 总页数 104
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 原子核物理学、高能物理学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号