The ability to form multiple component heterostructures of two-dimensional materials promises to provide access to hybrid materials with tunable properties different from those of the bulk materials or two-dimensional constituents. By taking advantage of the unique properties of different constituents, numerous applications are possible for which none of the individual components are viable. The synthesis of multiple component heterostructures, however, is nontrivial, relying on either the cleaving and stacking of bulk materials in a “scotch tape” type technique or finding coincidentally favorable growth conditions which allow layers to be grown epitaxially on each other in any order. In addition, alloying of miscible materials occurs when the modulation wavelength is small. These synthetic challenges have limited the ability of scientists to fully utilize the potential of multiple component heterostructures. An alternative synthetic route to multiple component heterostructures may be found through expansion of the modulated elemental reactant technique which allows access to metastable products, known as ferecrystals, which are otherwise inaccessible.
This work focuses on the expansion of the modulated elemental reactants technique for the formation of ferecrystals containing multiple constituents. As a starting point, the synthesis of the first alloy ferecrystals (SnSe)1.16-1.09([NbxMo1-x]Se2) will be discussed. The structural and electrical characterization of these compounds will then be used to determine the intermixing of the first three component ferecrystal heterojunction ([SnSe]1+δ)([{MoxNb1-x}Se2]1+γ)([SnSe]1+δ)({NbyMo1-y}Se2). Then, by synthesizing ([SnSe]1+δ)m([{MoxNb1-x}Se2]1+γ)1([SnSe]1+δ)m({NbxMo1-x}Se2)1 (m = 0 - 4) compounds with increasing thicknesses of SnSe, the interdiffusion of miscible constituents in ferecrystals will be studied. In addition, by comparison of the ([SnSe]1+δ)m ([{MoxNb1-x}Se2]1+γ)1([SnSe]1+δ)m({NbxMo1-x}Se2)1 (m = 0 - 4) compounds to the ([SnSe]1+δ)m(NbSe2)1 (m = 1 - 8) compounds the electronic interactions of the MoSe2 and NbSe2 layers will be determined. Finally, the effects of different alloying strategies and the interdiffusion of miscible constituents will be further examined by the synthesis of ordered ([SnSe]1.15)1([TaxV1-x]Se2)1([SnSe]1.15)1([VyTa1-y]Se2)1 and ([SnSe]1+δ) ([TaxV1-x]Se2) compounds with the effect of isoelectric doping on the charge density wave transition in (SnSe)1.15(VSe2) also being explored.
This work contains previously published and unpublished co-authored material.
| Identifer | oai:union.ndltd.org:uoregon.edu/oai:scholarsbank.uoregon.edu:1794/19712 |
| Date | 23 February 2016 |
| Creators | Westover, Richard |
| Contributors | Boettcher, Shannon |
| Publisher | University of Oregon |
| Source Sets | University of Oregon |
| Language | en_US |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Rights | All Rights Reserved. |
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