Optoelectronic properties of novel junctions in one-dimensional semiconductors
[Thesis]
Mark T. Triplett
Yu, Dong
University of California, Davis
2014
75
Committee members: Chiang, Shirley; Islam, M. Saif
Place of publication: United States, Ann Arbor; ISBN=978-1-321-36411-8
Ph.D.
Physics
University of California, Davis
2014
One-dimensional (1D) materials have been extensively studied due to their beneficial effects on device performance and interesting and unique material properties. The study of junctions in 1D materials is a natural extension to the physics of nanostructured materials because junctions in materials are ubiquitous for all device technologies. In order for 1D materials to be incorporated into real world devices, a complete understanding of the influence of junctions, including their optoelectronic, mechanical, chemical, and structural properties will be paramount. In this dissertation, extensive investigation into the properties of junctions in 1D materials is conducted utilizing optoelectronic, mechanical, and computational characterization techniques such as scanning photocurrent microscopy, electron beam induced current, and finite element method simulations. These techniques were used to study metal-insulator junctions in 1D geometries, nanowire bridge devices which are fabricated with 1D homojunctions, self-welded junctions between nanowires, and ensemble devices made from arrays of 1D materials. The findings from these studies included previously undiscovered metal-insulator band offsets in strongly correlated materials, long minority carrier diffusion lengths in nanowires, interesting optoelectronic properties of nanowire-nanowire junctions, and novel and robust mechanical properties of flexible 1D ensemble devices. These findings have implications for future potential nanotechnology based device applications and materials physics studies.