Carrier distribution and dynamics of nanocrystal solids doped with artificial atoms.
Single component and multicomponent nanocrystal (NC) solids represent an exciting new form of condensed matter, as they can potentially capture not only the quantum features of the individual building blocks but also novel collective properties through coupling of NC components. Unlike bulk semiconductors, however, there is no current theory for how introduction of dopants will impact the electronic structure and transport properties of NC solids. Empirically, it is known that in semiconductor NC systems, mixing two different materials of NCs electronically dopes the film. However, it has been challenging to connect the macroscopic measurements of doping effects on transport behavior to a microscopic understanding of how the identity, placement, and abundance of dopants impact these measurements. In this Letter, we report the first temperature-dependent thermopower measurements in doped and undoped NC solids. In combination with temperature-dependent electrical conductivity measurements, how the doping affects the carrier concentration as well as mobility is explored exclusively. These complementary measurements serve as a unique electronic spectroscopy tool to quantitatively reveal the energetics of carriers and electronic states in NC solids.
Ko
Dong-Kyun
DK
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Urban
Jeffrey J
JJ
Murray
Christopher B
CB
D004579:Electron Transport; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size