Probing and Manipulating the Luminescence Properties of Porous Semiconductor Nanoparticles

位于圣巴巴拉的加州大学的Steven Buratto得到了实验物理化学计划的支持，其研究旨在探测和操纵多孔硅纳米颗粒的发光特性。 为了避免有害的平均效应，光学性质将探测孤立的纳米粒子来自散装多孔硅，使用单分子光谱技术。 项目目标包括详细了解这些纳米颗粒的发光特性，以及这些特性如何取决于表面功能，发射硅量子点的大小（即体多孔硅的孔隙率）和硅原材料的掺杂浓度。 另一个目标是更准确地将发光物质的尺寸与发光波长相关联，以便确定量子限制的程度。 最后，实验将通过测量样品发射中的反聚束来确定所研究的单个纳米颗粒是否由单个两能级系统组成。 结果有望使新的理解纳米颗粒的发光性能，在多孔硅作为一种光学材料的发展援助，并建议新的方向，以最大限度地提高多孔硅的光学性能。由于多孔硅在光电子器件和激光器中的应用，以及与当前硅加工技术集成的潜力，在过去几年中，对多孔硅可见光发射的观察引起了极大的兴趣。 十多年前首次观察到多孔硅的发光，从那时起，科学家们一直在努力开发一种机制来描述这种材料的物理特性。 虽然仍然缺乏一致的物理描述，但已经利用多孔硅的可调发光和高表面积生产了大量的测试器件。 这些器件包括分子传感器、发光二极管、光开关和光伏电池。 这项研究的成功结果预计将影响使用多孔硅的进一步有用设备的开发。

Steven Buratto of the University of California at Santa Barbara is supported by the Experimental Physical Chemistry Program for research that aims to probe and manipulate luminescence properties of porous silicon nanoparticles. To avoid deleterious averaging effects, optical properties will be probed on isolated nanoparticles derived from bulk porous silicon, using single molecule spectroscopic techniques. Project goals include obtaining a detailed understanding of the luminescence properties of these nanoparticles and how such properties depend on the surface functionality, the size of the emitting silicon quantum dot (i.e. porosity of the bulk porous silicon) and the dopant concentration of the silicon starting material. Another goal is to correlate more accurately the size of the emitting species with the luminescence wavelength, in order to determine the degree of quantum confinement. Finally, experiments will determine if the single nanoparticles under study consist of a single two-level system by measuring antibunching in the sample emission. Outcomes are expected to enable new understandings of nanoparticle luminescence properties, aid in the development of porous silicon as an optical material, and suggest new directions to maximize the optical properties of porous silicon. The observation of visible light emission from porous silicon has stimulated tremendous interest over the past several years due to its applications in optoelectronic devices and lasers, and the potential for integration with current silicon processing technologies. Luminescence from porous silicon was first observed over a decade ago, and since that time scientists have struggled to develop a mechanism to describe the photophysical properties of this material. Although a consistent physical description is still lacking, a host of test devices has been produced making use of the tunable luminescence and high surface area of porous silicon. These devices include molecular sensors, light emitting diodes, optical switches, and photovoltaic cells. Successful outcomes for this research are expected to impact the development of further useful devices using porous silicon.