CAREER: Continuous-flow microplasma synthesis of Group IV semiconductor nanoparticles

Case Western Reserve University, Cleveland OH

Investigators

Abstract

CBET-0746821, Sankaran In the semiconductor industry, plasma-based surface processes such as reactive ion etching and chemical vapor deposition of thin films are vitally important to the manufacturing of integrated circuits. Under certain operating conditions, the formation of small particles in the gas phase has been observed known as a dusty plasma. While plasma synthesis of nanoparticles is attractive for nanotechnological applications, in these ?batch? processes, it is difficult to control particle nucleation and growth in order to obtain narrow dispersions of nanometer-sized particles. In addition, the low operating pressures (<10 Torr) and large infrastructure normally associated with these processes makes it difficult to scale-up for commercial applications. This research focuses on the synthesis of narrowly dispersed, surface-functionalized Group IV semiconductor nanoparticles including silicon and diamond. The Group IV semiconductors are important materials because of their excellent electrical and chemical properties and compatibility with microelectronics processing. However, fundamental understanding of nanoscale properties in these materials remains unknown because of synthetic challenges. Here, a synthesis methodology is proposed based on a continuous-flow, atmospheric-pressure microplasma. Microplasmas are miniaturized versions of direct-current (dc) glow discharges characterized by large concentrations of energetic electrons (1-10 eV) which stabilize the plasma at high pressures. Because of the small volume defined by the microplasma (less than 1 nL), particle growth is restricted, allowing the production of nanometer-sized, non-agglomerated particles. Continuous production of nanoparticles at atmospheric pressure will be monitored by aerosol size classification to obtain particle size distributions in real time. In addition, the particles will be collected and characterized by high-resolution transmission electron microscopy (HRTEM), micro-Raman spectroscopy, and photoluminescence (PL). The availability of precisely tuned silicon and diamond nanoparticles will lead to a fundamental understanding of electronic confinement in these materials. Broader impacts: The research is closely integrated with educational activities that include the establishment of a new program for young women in K-12 schools. The program is comprised of two components: 1) expose middle school and high school students to research in current technological areas including nanotechnology through a new research-based elective class and 2) provide high school students an opportunity to conduct independent research at the university. The outreach activities are expected to enhance the education of students in math and science by exposing them to the practice of science and engineering.