CAREER: Developing Advanced Morphological Control of Nanowires to Encode Photonic and Optoelectronic Functionality

非技术描述：半导体纳米线由于其潜在的电子和光子应用而被广泛探索，并且线的性质在很大程度上取决于在合成期间调节其组成的能力。该项目旨在探索基于化学的工艺来编码复杂的圆柱形硅线，并了解硅纳米线在生长过程中磷，硼和氮掺杂剂原子的掺入。线合成条件对这些掺杂剂原子的浓度和空间分布的影响进行了研究，并评估了原子突变界面的潜力。此外，掺杂剂原子对线的光学性质和形状的影响进行了检查，针对螺旋纳米线的优化生长和线内的发光中心的可控创建。该项目培训本科生和研究生的主题，桥梁之间的接口化学，物理和工程-提供在纳米材料合成，微细加工，光电测量和建模的经验广度。小学和地方图书馆的各种方案和示范、每年的公共科学博览会和高中学生的夏季研究使科学概念得到广泛传播。技术说明：半导体纳米线通常通过使用气-液-固（VLS）和气-固-固（VSS）生长工艺的金属催化生长来合成。该项目旨在开发一种组合的VLS-VSS生长方法，以单个或亚纳米空间分辨率编码硅纳米线中的磷，硼和氮掺杂剂原子。掺杂剂的掺入用于调节纳米线的光学性质和形态。例如，共掺杂被探索作为一种新的方法来创建手性线，这些结构的手征光学响应进行了研究。此外，氮的掺入用于引入具有发光特性的缺陷态。采用硼和磷的调制来创建深亚波长光子晶体腔，该光子晶体腔与具有波长选择性检测的p-n结光电探测器集成。这些努力扩展了一套自下而上的合成方法，可用于编码纳米线中的光子和光电功能。

Nontechnical Description: Semiconductor nanowires have been widely explored for their potential electronic and photonic applications, and the properties of the wires are largely dictated by the ability to modulate their composition during synthesis. This project aims to explore chemistry-based processes to encode complex cylindrical silicon wires and to understand the incorporation of phosphorus, boron, and nitrogen dopant atoms in silicon nanowires during their growth. The effect of wire synthesis conditions on the concentration and spatial profiles of these dopant atoms is studied, and the potential for atomically-abrupt interfaces is evaluated. In addition, the influence of the dopant atoms on the optical properties and shape of the wires is examined, targeting optimized growth of spiraling nanowires and controllable creation of luminescent centers within the wires. The project trains undergraduate and graduate students in topics that bridge the interface between chemistry, physics, and engineering - providing breadth of experience in nanomaterials synthesis, microfabrication, optoelectronic measurements, and modeling. Various programs and demonstrations in elementary schools and local libraries, annual public science expositions and summer research for high-school students enable broad dissemination of the scientific concepts. Technical Description: Semiconductor nanowires are often synthesized by metal-catalyzed growth using vapor-liquid-solid (VLS) and vapor-solid-solid (VSS) growth processes. This project aims to develop a combined VLS-VSS growth method to encode phosphorus, boron, and nitrogen dopant atoms in silicon nanowires with single or sub-nanometer spatial resolution. The incorporation of dopants is used to modulate the optical properties and morphology of the nanowires. For instance, co-doping is explored as a novel method to create chiral wires, and the chiro-optical response of these structures is studied. In addition, the incorporation of nitrogen is used to introduce defect states with luminescent characteristics. Modulation of boron and phosphorus is employed to create deep-subwavelength photonic crystal cavities integrated with p-n junction photodetectors that exhibit wavelength-selective detection. These efforts expand the set of bottom-up synthetic methods that can be used to encode photonic and optoelectronic functionality in nanowires.