Electron transport through semiconductor nanocrystal (NC) systems is almost entirely understood by analogs to bulk science. The physics governing electron transport within NCs is entirely analogous to bulk semiconductors with extreme spatial constraints. In contrast, the physics of electrons conducting between NCs is understood through the physics of amorphous materials, granular metals, or bulk semiconductors, depending on the structure of the NC ensemble. Herein is an investigation of how dopant distribution engineering can be utilized to modulate near surface depletion in NC films. The dependence of NC film conductivity on dopant distribution is eliminated by surface passivation. A code to fit the optical absorption of colloidal NCs is developed to account for surface scattering, depletion, size heterogeneity, and dopant heterogeneity. This code is used to define the conduction within an individual NC. The intra-NC conduction is used as a metric to describe and define the phase diagram of NC film electron transport. Using the criteria developed here, we make metallic films in a controlled manner.
This work illustrates an overview of bulk electron transport and an introduction of NC film electron transport in Chapter 1. These descriptions will then be used to investigate the powerful capability to engineer intra-NC dopant distribution to manipulate NC film conductivity in Chapter 2. The intra-NC conductance is then investigated using a novel code to fit the optical absorption of NCs in Chapter 3. With a deep understanding of intra-NC transport, the electron transport phase diagram is constructed in Chapter 4.Chemical Engineerin
