Ultrafast spectroscopy of materials and devices

材料和器件的超快光谱

• 批准号: 203501-2011
• 负责人: Hegmann, Frank
• 金额: $ 3.5万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569956
• 关键词: Ultrafast; spectroscopy; materials; devices

What happens when light is absorbed in a material? If electrons in the material are excited to higher energy levels, do they break free and move around inside the material or do they get stuck somehow? When they finally get back to their original state in the material, do they get rid of their excess energy by emitting light or by shaking the atoms around them in the material? And how long does it take for them to do all that? These are the types of questions scientists ask when trying to understand the nature of new materials that may someday find their way into the latest electronic devices. Many fundamental processes in materials such as charge carrier photogeneration, transport, relaxation and recombination occur over very fast time scales much shorter than a billionth of a second (less than a nanosecond). In addition, the characteristic energy scales associated with a given process can vary greatly between different material systems. In order to better understand such ultrafast processes in materials and to study their effect in device structures, it is therefore essential to use ultrafast spectroscopic techniques that can excite and probe samples over a wide range of wavelengths and length scales with sub-picosecond time resolution (i.e., less than a thousandth of a nanosecond, which is the same amount of time it takes light to travel only a third of a millimeter!) In the Ultrafast Spectroscopy Lab and Ultrafast Nanotools Lab, we use a variety of advanced laser sources to study ultrafast phenomena in materials and devices, providing valuable insight into the nature of new materials and the ultimate switching speeds and response times of devices. We explore ultrafast carrier dynamics and transport in semiconductors, organic semiconductors, and nanomaterials, and explore how intense light interacts with materials. Ultrafast carrier dynamics in materials over nanometer length scales and even in single molecules will be explored using leading-edge scanning probe instruments coupled to an ultrafast laser source in the new Ultrafast Nanotools Lab, which is unique in the world.

当光被材料吸收时会发生什么？如果材料中的电子被激发到更高的能级，它们是会挣脱束缚在材料内部移动，还是会以某种方式被卡住？当它们最终回到材料中的原始状态时，它们是通过发光还是通过震动材料中它们周围的原子来消除多余的能量？他们做这些需要多长时间？这些是科学家们在试图了解新材料的性质时提出的问题，这些新材料有朝一日可能会进入最新的电子设备。 材料中的许多基本过程，如电荷载流子光生、输运、弛豫和复合，都发生在比十亿分之一秒（小于1纳秒）短得多的非常快的时间尺度上。此外，与给定过程相关的特征能量尺度在不同的材料系统之间可以有很大的变化。为了更好地理解材料中的这种超快过程并研究它们在器件结构中的影响，因此必须使用超快光谱技术，该技术可以在宽范围的波长和长度尺度上以亚皮秒时间分辨率（即，不到千分之一纳秒，这与光传播三分之一毫米所需的时间相同！） 在超快光谱实验室和超快纳米工具实验室，我们使用各种先进的激光源来研究材料和器件中的超快现象，为新材料的性质以及器件的最终开关速度和响应时间提供有价值的见解。我们探索半导体，有机半导体和纳米材料中的超快载流子动力学和传输，并探索强光如何与材料相互作用。超快载体动力学在纳米长度尺度上的材料，甚至在单分子将使用先进的扫描探针仪器耦合到超快激光源在新的超快纳米工具实验室，这是世界上独一无二的探索。