Browsing by Author "Silva-Quinones, Dhamelyz"
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Item Attachment Chemistry of 4-Fluorophenylboronic Acid on TiO2 and Al2O3 Nanoparticles(Chemistry of Materials, 2022-12-13) Byron, Carly; Silva-Quinones, Dhamelyz; Sarkar, Sucharita; Brown, Scott C.; Bai, Shi; Quinn, Caitlin M.; Grzenda, Zachary; Chinn, Mitchell S.; Teplyakov, Andrew V.Surface modification of nanoparticulate TiO2 and Al2O3 materials with 4-fluorophenylboronic acid is investigated in order to both evaluate the novel surface modification schemes and develop spectroscopic labels for surface characterization. The chemistry of the modification is followed on all these surfaces using X-ray photoelectron spectroscopy, multinuclear (11B, 19F, and 13C) solid-state and solution NMR, and infrared spectroscopy to determine the binding modes of this compound using boron and fluorine as probe atoms. Density functional theory model calculations are utilized to visualize predicted surface species and to interpret the results of spectroscopic measurements. A comparison is made among TiO2 rutile, TiO2 anatase, and γ-Al2O3. On all three materials, the modification proceeds via the boronic functional groups, with metal oxide-controlled surface chemistry. The bonding configuration depends on the material and is dominated by a monodentate species for titania and by bidentate species for alumina. The surface structures determined to form on all the oxide semiconductors investigated suggest that sensitization or monolayer doping approaches with a well-defined chemical interaction via a boronic functionality can be developed.Item Monolayer functionalization of silicon and metal oxide surfaces with boron- and nitrogen-containing precursors(University of Delaware, 2024) Silva-Quinones, DhamelyzAs the dimensions of electronic device components shrink, there is a growing need for innovative methods and chemical modification strategies to fabricate nanometer-sized features. The work outlined in this dissertation focuses on two main strategies: the ultra-shallow monolayer doping, and area selective deposition. These strategies necessitate a detailed understanding of the interactions between different precursors and substrates, as well as the development of innovative techniques for governing and manipulating these interactions. ☐ In the following chapters, a novel chemical method for the monolayer functionalization of silicon surfaces with boron- and nitrogen-containing precursors is discussed and proposed as a pathway for ultra-shallow monolayer doping. ☐ Secondly, the monolayer functionalization of metal-oxide surfaces with an organic precursor with unique spectroscopic labels was investigated in order to understand the attachment chemistry of these materials and to develop spectroscopic labels for surface characterization. ☐ And lastly, the use of an organic molecule with unique spectroscopic labels is proposed as an effective resist to block the growth of materials in area selective deposition. ☐ The goals for the research contained in this dissertation are: • 1) Modify the surface of the semiconductor to form direct dopant (B, N)-Si bonds and control the concentration of the dopant. • 2) Explore and control the attachment of the boron-containing precursor that contains unique spectroscopic labels (F, B) with the metal-oxide surfaces. • 3) Modify the chemical reactivity of the surfaces with respect to a metal-organic precursor to inhibit or promote the deposition of TiO2 films. ☐ To achieve these goals, a combination of spectroscopic, microscopic and computational investigations was performed to study the surface chemical modifications processes. X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and solid-state nuclear magnetic resonance spectroscopy (ss-NMR) were used to elucidate the chemical environment and to determine the binding modes of the attached compounds on the surfaces. Atomic force microscopy (AFM) was utilized to evaluate the surface morphological changes after the surface chemical modifications. Also density functional theory (DFT) calculations were utilized to supplement the analysis, interpret the results of spectroscopic measurements and to interrogate surface stability of possible surface species.Item The Effect of Surface Terminations on the Initial Stages of TiO2 Deposition on Functionalized Silicon(ChemPhysChem, 2023-01-10) Parke, Tyler; Silva-Quinones, Dhamelyz; Wang, George T.; Teplyakov, Andrew V.As atomic layer deposition (ALD) emerges as a method to fabricate architectures with atomic precision, emphasis is placed on understanding surface reactions and nucleation mechanisms. ALD of titanium dioxide with TiCl4 and water has been used to investigate deposition processes in general, but the effect of surface termination on the initial TiO2 nucleation lacks needed mechanistic insights. This work examines the adsorption of TiCl4 on Cl−, H−, and HO− terminated Si(100) and Si(111) surfaces to elucidate the general role of different surface structures and defect types in manipulating surface reactivity of growth and non-growth substrates. The surface sites and their role in the initial stages of deposition are examined by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Density functional theory (DFT) computations of the local functionalized silicon surfaces suggest oxygen-containing defects are primary drivers of selectivity loss on these surfaces. Graphical Abstract available at: https://doi.org/10.1002/cphc.202200724 Deposition of TiO2 from TiCl4 and water dosing cycles onto H- and Cl-terminated silicon surfaces is defined by the interaction of the adsorbate molecule with defects on these surfaces. The nature of these defects and their effect on selectivity of deposition are investigated.