• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Nature >Soft surfaces of nanomaterials enable strong phonon interactions
【24h】

Soft surfaces of nanomaterials enable strong phonon interactions

机译：纳米材料的柔软表面可实现强声子相互作用

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

Phonons and their interactions with other phonons, electrons or photons drive energy gain, loss and transport in materials. Although the phonon density of states has been measured and calculated in bulk crystalline semiconductors(1), phonons remain poorly understood in nanomaterials(2-5), despite the increasing prevalence of bottom-up fabrication of semiconductors from nanomaterials and the integration of nanometre-sized components into devices(6-8). Here we quantify the phononic properties of bottom-up fabricated semiconductors as a function of crystallite size using inelastic neutron scattering measurements and ab initio molecular dynamics simulations. We show that, unlike in microcrystalline semiconductors, the phonon modes of semiconductors with nanocrystalline domains exhibit both reduced symmetry and low energy owing to mechanical softness at the surface of those domains. These properties become important when phonons couple to electrons in semiconductor devices. Although it was initially believed that the coupling between electrons and phonons is suppressed in nanocrystalline materials owing to the scarcity of electronic states and their large energy separation(9), it has since been shown that the electron-phonon coupling is large and allows high energy-dissipation rates exceeding one electronvolt per picosecond (refs 10-13). Despite detailed investigations into the role of phonons in exciton dynamics, leading to a variety of suggestions as to the origins of these fast transition rates(14,15) and including attempts to numerically calculate them(12,13,16), fundamental questions surrounding electron-phonon interactions in nanomaterials remain unresolved. By combining the microscopic and thermodynamic theories of phonons(1,17-19) and our findings on the phononic properties of nanomaterials, we are able to explain and then experimentally confirm the strong electron-phonon coupling and fast multi-phonon transition rates of charge carriers to trap states. This improved understanding of phonon processes permits the rational selection of nanomaterials, their surface treatments, and the design of devices incorporating them.
机译：声子及其与其他声子，电子或光子的相互作用推动了材料的能量获取，损失和传输。尽管已经测量并计算了大块晶体半导体中的声子密度（1），但尽管纳米材料自下而上地制造半导体的普及率不断提高，并且纳米技术的集成化程度不断提高，但纳米材料中的声子仍知之甚少（2-5）。将组件调整为设备大小（6-8）。在这里，我们使用非弹性中子散射测量和从头算分子动力学模拟来量化自底向上制造的半导体的声子性质，作为微晶尺寸的函数。我们表明，与微晶半导体不同，具有纳米晶畴的半导体的声子模由于在这些畴表面的机械柔软性而显示出降低的对称性和低能量。当声子耦合到半导体器件中的电子时，这些特性变得很重要。尽管最初认为由于电子态的稀缺及其大的能量分离（9），纳米晶材料中电子与声子之间的耦合受到抑制（9），但此后表明电子-声子的耦合很大并且允许高能-耗散速率超过每皮秒1电子伏特（参考文献10-13）。尽管对声子在激子动力学中的作用进行了详尽的研究，但对这些快速跃迁速率的起源提出了各种建议（14,15），包括尝试对它们进行数值计算（12,13,16），围绕这些基本问题纳米材料中的电子-声子相互作用仍未解决。通过结合声子的微观和热力学理论（1,17-19）以及我们对纳米材料的声子性质的发现，我们能够解释并通过实验证实强的电子-声子耦合和快速的多声子跃迁速率运营商陷阱国家。对声子过程的这种更好的理解使得可以合理地选择纳米材料，对其表面进行处理以及设计包含纳米材料的设备。

著录项

  • 来源
    《Nature》 |2016年第7596期|618-622|共5页
  • 作者

    Bozyigit Deniz; Yazdani Nuri; Yarema Maksym; Yarema Olesya; Lin Weyde Matteo Mario; Volk Sebastian; Vuttivorakulchai Kantawong; Luisier Mathieu; Juranyi Fanni; Wood Vanessa;

  • 作者单位

    ETH, Dept Informat Technol & Elect Engn, Lab Nanoelect, CH-8092 Zurich, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Lab Nanoelect, CH-8092 Zurich, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Lab Nanoelect, CH-8092 Zurich, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Lab Nanoelect, CH-8092 Zurich, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Lab Nanoelect, CH-8092 Zurich, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Lab Nanoelect, CH-8092 Zurich, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Nano TCAD Grp, CH-8092 Zurich, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Nano TCAD Grp, CH-8092 Zurich, Switzerland;

    Paul Scherrer Inst, Lab Neutron Scattering & Imaging, CH-5232 Villigen, Switzerland;

    ETH, Dept Informat Technol & Elect Engn, Lab Nanoelect, CH-8092 Zurich, Switzerland;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 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