Date of Award
Summer 8-2016
Degree Name
Master of Science (MS)
Degree Type
Thesis
Abstract
Nanocrystal assemblies are being explored for a number of optoelectronic applications such as transparent conductors, photovoltaic solar cells, and electrochromic windows. Majority carrier transport is important for these applications, yet it remains relatively poorly understood in films comprised of touching nanocrystals. Specifically, the underlying structural parameters expected to determine the transport mechanism have not been fully elucidated. In this report, we demonstrate experimentally that the contact radius, between touching heavily doped ZnO nanocrystals, controls the electron transport mechanism. Spherical nanocrystals are considered, which are connected by a circular area. The radius of this circular area is the contact radius. For nanocrystals that have local majority carrier concentration above the Mott transition, there is a critical contact radius. If the contact radius between nanocrystals is less than the critical value, then the transport mechanism is variable range hopping. If the contact radius is greater than the critical value, the films display behavior consistent with metallic electron transport.
Language
English (en)
Chair
Dr. Elijah Thimsen
Committee Members
Dr. Elijah Thimsen Dr. Pratim Biswas Dr. Bryce Sadtler
Included in
Engineering Science and Materials Commons, Nanoscience and Nanotechnology Commons, Semiconductor and Optical Materials Commons
Comments
The following thesis has been reprinted with permission from: Contact Radius and the Insulator–Metal Transition in Films Comprised of Touching Semiconductor Nanocrystals, Deanna Lanigan and Elijah Thimsen, ACS Nano 2016 10 (7), 6744-6752, DOI: 10.1021/acsnano.6b02190