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Thesis Amol Ratnaparkhe.pdf (6.8 MB)

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FIRST PRINCIPLES STUDY OF ELECTRONIC AND VIBRATIONAL PROPERTIES OF WIDE BAND GAP OXIDE AND NITRIDE SEMICONDUCTORS

Ratnaparkhe, Amol
http://orcid.org/0000-0002-9967-2434
http://rave.ohiolink.edu/etdc/view?acc_num=case1619606222502271

Abstract Details

2021, Doctor of Philosophy, Case Western Reserve University, Physics.
The ever-increasing number of applications requiring semiconductor materials at their core is driving the need to understand certain oxide and nitride materials. In this thesis, we investigate two of such classes. The first of those is the class of wide band-gap oxides and includes materials like β-〖Ga〗_2 O_3 and the 〖(〖Al〗_x 〖Ga〗_(1-x))〗_2 O_3 alloy system. β-〖Ga〗_2 O_3 is the most stable of the five phases in which 〖Ga〗_2 O_3 is found to exist. With a significantly high experimentally measured band gap of 4.5-4.9 eV, it is touted to be an excellent material for high-power electronics and UV transparent optoelectronic applications. Using first-principles calculations, we study this material and present the electronic band structure calculations using the quasiparticle self-consistent GW method. Next, we extend this study to the alloy system 〖(〖Al〗_x 〖Ga〗_(1-x))〗_2 O_3 in which 〖Ga〗_2 O_3 is alloyed with an even higher band-gap material, 〖Al〗_2 O_3. We study the system in both the phases, α and β, present the electronic band structures for varying compositions of Al ranging from 0% to 100%, and predict the most favorable composition and phase for such an alloy to exist. The second class of materials in this thesis is the alloy system formed by the combination of group III- and II-IV nitrides, GaN and 〖ZnGeN〗_2, respectively. In particular, we study the vibrational properties of 〖ZnGeGa〗_2 N_4. 〖ZnGeGa〗_2 N_4, at 50% composition, is an octet-preserving and lowest energy superlattice of half a cell of 〖ZnGeN〗_2 and half GaN along the b-axis of 〖ZnGeN〗_2 in the 〖Pbn2〗_1 structure. Using Density Functional perturbation theory implemented in ABINIT, the phonon modes at the zone center, Γ allow us to calculate longitudinal optical-transverse optical splittings using Born effective charges. In addition, the IR and Raman spectra along with the phonon density of states, and the phonon band structure are presented. Lastly, we study the transition metal oxide, 〖MoO〗_3. We present the vibrational properties of orthorhombic α-〖MoO〗_3 with an emphasis on the IR and Raman spectra. We find good agreement with experimental IR and Raman studies of this materials, obtain its Born effective charges and explain the nature of the complex vibrational modes.
Walter Lambrecht (Advisor)
159 p.
Condensed Matter Physics; Materials Science; Physics
Electronic band structure; vibrational properties; wide-bandgap; alloy system; nitride semiconductors; QSGW; ABINIT; IR, and Raman spectra

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Citations

  • Ratnaparkhe, A. (2021). FIRST PRINCIPLES STUDY OF ELECTRONIC AND VIBRATIONAL PROPERTIES OF WIDE BAND GAP OXIDE AND NITRIDE SEMICONDUCTORS [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1619606222502271

    APA Style (7th edition)

  • Ratnaparkhe, Amol. FIRST PRINCIPLES STUDY OF ELECTRONIC AND VIBRATIONAL PROPERTIES OF WIDE BAND GAP OXIDE AND NITRIDE SEMICONDUCTORS. 2021. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1619606222502271.

    MLA Style (8th edition)

  • Ratnaparkhe, Amol. "FIRST PRINCIPLES STUDY OF ELECTRONIC AND VIBRATIONAL PROPERTIES OF WIDE BAND GAP OXIDE AND NITRIDE SEMICONDUCTORS." Doctoral dissertation, Case Western Reserve University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1619606222502271

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.
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