Systematic tuning of silicon Schottky barrier height by atomic interlayers with low electronegativities
Item
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Title
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Systematic tuning of silicon Schottky barrier height by atomic interlayers with low electronegativities
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Identifier
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d_2009_2013:75c950763648:11444
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identifier
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11914
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Creator
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Long, Wei,
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Contributor
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Raymond T. Tung
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Date
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2012
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Language
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English
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Publisher
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City University of New York.
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Subject
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Atomic physics | Materials science | Fermi Level | Inhomogeneity | Interface | Schottky Barrier
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Abstract
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The Schottky barrier height (SBH) is of great importance to the functionality of semiconductor devices, as it governs the carrier transport across the metal-semiconductor (MS) interface. The presence of the Fermi level (FL) pinning phenomena makes tuning the SBH a difficult goal to achieve. The technique of "partisan interlayer" (PI) was proposed recently to modify the SBH, where stable adsorbate-terminated semiconductor (ATS) surfaces were used to form SBs with subsequently applied metal. When elements with large electronegativities were used to form the ATS, the PI technique was effective in reducing the n-type SBH and increasing the p-type SBH, driven by the expected transfer of charge from the semiconductor to the adsorbates. In this thesis work, elements with electronegativities smaller than that of the semiconductor are used as surface termination. SBHs for Ag, Au and In on Si surfaces are found to increase for the n-type and decrease for the p-type interfaces, by as much as 0.25eV, when Ga, Mg and K are used to terminate the Si surfaces. The present results are thus in agreement with the expected charge transfers from elements with smaller electronegativities to silicon and illustrate the general validity of the PI technique. The chemical stability of these surfaces likely weakens the MS interaction and leads to the (partial) preservation of the surface dipole at the MS interface. However, large degrees of SBH inhomogeneity are observed for diodes on these surfaces, likely due to insufficient stability of these surfaces to completely withstand metal interaction. These results are discussed within the basic models of SBH formation and the implications of these results for SBH control of MS systems are also addressed.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Physics
