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Structure, Chemistry, and Energetics of Organic and Inorganic Adsorbates on Ga-rich GaAs and GaP(00l) Surfaces


Jeon, Seokmin (2014) Structure, Chemistry, and Energetics of Organic and Inorganic Adsorbates on Ga-rich GaAs and GaP(00l) Surfaces. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/1T2B-J793.


The work described in this dissertation includes fundamental investigations into three surface processes, namely inorganic film growth, water-induced oxidation, and organic functionalization/passivation, on the GaP and GaAs(001) surfaces. The techniques used to carry out this work include scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. Atomic structure, electronic structure, reaction mechanisms, and energetics related to these surface processes are discussed at atomic or molecular levels.

First, we investigate epitaxial Zn3P2 films grown on the Ga-rich GaAs(001)(6×6) surface. The film growth mechanism, electronic properties, and atomic structure of the Zn3P2/GaAs(001) system are discussed based on experimental and theoretical observations. We discover that a P-rich amorphous layer covers the crystalline Zn3P2 film during and after growth. We also propose more accurate picture of the GaP interfacial layer between Zn3P2 and GaAs, based on the atomic structure, chemical bonding, band diagram, and P-replacement energetics, than was previously anticipated.

Second, DFT calculations are carried out in order to understand water-induced oxidation mechanisms on the Ga-rich GaP(001)(2×4) surface. Structural and energetic information of every step in the gaseous water-induced GaP oxidation reactions are elucidated at the atomic level in great detail. We explore all reasonable ground states involved in most of the possible adsorption and decomposition pathways. We also investigate structures and energies of the transition states in the first hydrogen dissociation of a water molecule on the (2×4) surface.

Finally, adsorption structures and thermal decomposition reactions of 1-propanethiol on the Ga-rich GaP(001)(2×4) surface are investigated using high resolution STM, XPS, and DFT simulations. We elucidate adsorption locations and their associated atomic structures of a single 1-propanethiol molecule on the (2×4) surface as a function of annealing temperature. DFT calculations are carried out to optimize ground state structures and search transition states. XPS is used to investigate variations of the chemical bonding nature and coverage of the adsorbate species.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:scanning tunneling microscopy, density functional theory, III-V semiconductors, GaAs, GaP, Zn3P2, alkanethiol
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Atwater, Harry Albert
Thesis Committee:
  • Goddard, William A., III (chair)
  • Atwater, Harry Albert
  • Lewis, Nathan Saul
  • Beauchamp, Jesse L.
Defense Date:30 September 2013
Non-Caltech Author Email:jeonsm78 (AT)
Record Number:CaltechTHESIS:10082013-111509695
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for ch. 3
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7976
Deposited By: Seokmin Jeon
Deposited On:31 Oct 2014 16:23
Last Modified:08 Nov 2023 00:12

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