Subscriber access provided by REGIS UNIV
C: Plasmonics; Optical, Magnetic, and Hybrid Materials
Correlation between Structure, Chemistry and Dielectric Properties of Iron Doped Gallium Oxide (Ga FeO) 2-x
x
3
Swadipta Roy, Mallesham Bandi, Vishal B Zade, Abraham Martinez, Vaithiyalingam Shutthanandan, Suntharampillai Thevuthasan, and Chintalapalle V Ramana J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.8b07921 • Publication Date (Web): 22 Oct 2018 Downloaded from http://pubs.acs.org on October 22, 2018
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
Correlation between Structure, Chemistry and Dielectric Properties of Iron Doped Gallium Oxide (Ga2-xFexO3) Swadipta Roy1,2, B. Mallesham1, Vishal B. Zade1, Abraham Martinez3, V. Shutthanandan3, S. Thevuthasan3, and C.V. Ramana1,* 1Center
for Advanced Materials Research (CMR), University of Texas at El Paso, 500 W University Ave, El Paso, Texas 79968, USA.
2Department
of Metallurgical, Materials and Biomedical Engineering,
University of Texas at El Paso, 500 W University Ave, El Paso, Texas 79968, USA. 3Environmental
Molecular Sciences Laboratory (EMSL), Pacific Northwest National Laboratory (PNNL), Richland, Washington 99352, USA.
*Corresponding Author: Email address:
[email protected] (C. V. Ramana) 1 ACS Paragon Plus Environment
The Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ABSTRACT Iron (Fe) doped gallium oxide (Ga2O3) compounds (Ga2-xFexO3; x=0.0-0.3; referred to GFO) were synthesized by the standard high-temperature solid-state chemical reaction method. Xray diffraction (XRD) analyses confirmed that the sintered GFO compounds stabilized in monoclinic crystal structure with C2/m space group. Local structure and chemical bonding analyses using X-ray absorption near edge structure (XANES) revealed that the Fe occupies octahedral and tetrahedral sites similar to Ga in parent Ga2O3 lattice without considerable changes in the local symmetry. Morphology of the GFO compounds is characterized by the presence of rod-shaped particle (from around 2.0-3.5 μm) features. The energy dispersive X-ray spectroscopy (EDS) confirmed the chemical stoichiometry of the GFO compounds, where the atomic ratio of the constituted elements is in accordance with the calculated concentration values. The frequency and temperature dependent dielectric properties of the GFO compounds exhibited the traditional dielectric dispersion behavior. Relatively high dielectric constant at lower frequencies is attributed to Maxwell-Wagner type of dielectric relaxation which primarily originated from uncompensated charges at electrode material interface. Based on the results and analyses, the effect of Fe content on the crystal structure, chemical bonding and local structure, and dielectric properties of Ga2xFexO3 compounds
is established.
2 ACS Paragon Plus Environment
Page 2 of 40
Page 3 of 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Physical Chemistry
I.
INTRODUCTION Wide band gap oxide dielectrics, such as ZrO2, HfO2, Ga2O3, and La2O3 and chemical
compounds based on these materials, are of continued recent interest due to their excellent electronic properties, optical phenomena and technological applications such as in microelectronics, low-loss dielectric nanoantenna, field effect transistor (FET), and complementary metal-oxide-semiconductor (CMOS).1–10 Ga2O3, one among these oxide dielectric materials, has been receiving significant attention in recent years due to its superior structural, chemical and electronic properties.1,2,4 Being a wide band gap (Eg∼4.9 eV) material, Ga2O3 finds numerous applications in optoelectronics, high power electronics, chemical sensing, dielectric coatings for solar cells and ultraviolet transparent conductive oxide (UV-TCO) in optical devices.3,11–13 The high breakdown field (8 MV/cm) of Ga2O3 offers excellent opportunities for the design and development of high power Schottky diodes and high-voltage field effect transistors.14 Gallium oxide exhibits five different polymorphs namely α, β, γ, δ, and ε.15 Among the different polymorphs of Ga2O3, β-Ga2O3 is thermodynamically more stable from ambient to until its melting point. Whereas other polymorphs α, γ, δ and ε are metastable and transforms into β phase at sufficiently high temperatures in air. The order of formation energies for different polymorphs is β < ε < α < δ
