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作者 Uhlrich, John J
書名 Surface chemistry and electronic properties of gallium nitride and zinc oxide for use in organic/inorganic hybrid electronic devices
國際標準書號 9781109283099
book jacket
說明 219 p
附註 Source: Dissertation Abstracts International, Volume: 70-07, Section: B, page: 4354
Adviser: Thomas F. Kuech
Thesis (Ph.D.)--The University of Wisconsin - Madison, 2009
The performance of organic electronic devices can be strongly influenced by the interactions at the interfaces with contact materials. Inorganic semiconductors with large band gaps, such as GaN and ZnO, have the potential to access energy states that are difficult to achieve with other materials. These chemically-prepared surfaces were then used in the formation of organic-inorganic interfaces using pentacene or poly(3-hexylthiophene), typical of those encountered in optical, electronic and photovoltaic applications. The interfacial electronic structure formed as a result of the chemical treatment and organic semiconductor deposition was studied using x-ray and ultraviolet photoelectron spectroscopies (XPS and UPS) in order to elucidate the impact of such treatments on device performance
By performing ex-situ solution-based aq-HCl treatments as well as vapor-phase treatments, it was determined that chlorine can chemically passivate the GaN surface and that adsorbed oxygen-containing contaminants from the ambient remove surface states and decrease band bending on both the n-GaN and p-GaN surfaces. In situ annealing in 10-4 Torr NH3 was not sufficient to remove all of the contamination. UPS measurements of pentacene on GaN indicated that the valence band maximum of GaN lies below the highest occupied molecular orbital of pentacene by ∼3 eV, a favorable alignment for hole-injection from GaN into pentacene. This implies that GaN may function as an ohmic hole-injection contact into organic materials of high ionization potential
The surface electronic properties of ZnO nanorods were altered by UV-ozone treatment, while negligible effect was observed on single crystal ZnO surfaces, showing that the two growth techniques result in material with different defect structures. Treatment of single crystal ZnO in an (NH4)2S x solution showed evidence of ZnS formation on the (000 1) and (1010) orientations, but not on the (0001) facet. The (0001) facet instead showed evidence that sulfur atoms formed a chemical passivation layer, displacing adsorbed hydroxyl groups on the surface. ZnO/P3HT photovoltaic devices fabricated on ozone and sulfide treated surfaces showed an increase in open- circuit voltage as a result of sulfide treatment
School code: 0262
Host Item Dissertation Abstracts International 70-07B
主題 Engineering, Chemical
Physics, Condensed Matter
Engineering, Materials Science
0542
0611
0794
Alt Author The University of Wisconsin - Madison
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