AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Plasmonic Properties of Phosphorus-doped and Boron-doped Silicon Nanocrystals
Nicolaas J. Kramer, KATELYN SCHRAMKE, Uwe R. Kortshagen, University of Minnesota
Abstract Number: 268 Working Group: Nanoparticles and Materials Synthesis
Abstract Gas phase synthesis of nanomaterials is a desirable alternative to liquid chemistry approaches due to the continuous production of high quality, ligand-free crystalline materials with no chemicals needed. Precursors, all of which are gaseous, are fed into a low pressure chamber where particles nucleate in the glow discharge of a nonthermal plasma. This technique is used to produce phosphorus-doped and boron-doped silicon nanocrystals (SiNCs) which exhibit localized surface plasmonic resonance (LSPR). Doped nanomaterials are interesting due to their potential for exciting optical and electronic properties. Argon is used for the bulk plasma, silane is used to produce silicon particles, and phosphine and diborane are flown as dopant precursors. The total flow rate ranges from 20 to 50 sccm with a synthesis pressure in the range of 1-2 Torr yielding very monodisperse nanocrystals around 8nm in size.
Plasmonic properties of semiconductor nanocrystals are unique in that they are able to be tuned not only by size, shape and composition but also by free carrier concentration. In this work, very different plasmonic behavior is observed for the two different dopant types. As synthesize phosphorus doped SiNCs exhibit plasmon resonance while the boron doped nanocrystals require post synthesis treatment before a LSPR is seen. The oxidation mechanism plays a key role in dopant dynamics in the nanomaterials as it leads to plasmon resonance in b-doped SiNCs and suppression of the plasmon resonance in p-doped SiNCs.
This work was supported by the Army Office of Research under MURI Grant W911NF-12-1-0407. Part of this work was carried out in the UMN Characterization Facility, which has received capital equipment funding from the NSF through the UMN MRSEC program and the Minnesota Nanocenter, which receives partial support from NSF through the NNIN program.