Amorphous ln-Sn-Zn-0
Department
Physics
Major
Physics
Research Advisor
Medvedeva, Julia E.
Advisor's Department
Physics
Funding Source
NSF-CEMRI Proposal
Abstract
Amorphous oxide semiconductors (AOSs) exhibit a rare combination of high optical transparency and high electron mobility surpassing that of amorphous silicon by orders of magnitude. Owing to the high electronegativity of oxygen anions and, hence, their strong interaction with metal cations, the network of metal-oxygen polyhedra is preserved on going from the crystalline to the amorphous state. Yet, variations in the oxygen coordination and distortions in the cation-anion chains alter the structure of valence and higher-energy conduction bands making it possible to tune the AOS properties. We employ first-principles density-functional calculations to investigate the structural and electronic properties of amorphous Zn-Sn-ln-0 and to determine how tensile strain affects the metal-oxygen bond lengths, bond angles, and coordination numbers in the oxide. Next, we identify the defect states responsible for the conductivity by calculating the atomic contributions to the valence and conduction band wave functions and characterize the defects structurally.
Biography
Mathew was born September 14, 1993 and raised in St. Louis County near Fenton. He graduated from Rockwood Summit high school. Received Eagle Scout in the Boy Scouts of America and was admitted to Missouri University of science and Technology in 2012. Mathew is majoring in physics and started research for Dr. Medvedeva.
Research Category
Sciences
Presentation Type
Oral Presentation
Document Type
Presentation
Location
Upper Atrium/Hallway
Presentation Date
03 Apr 2013, 9:00 am - 11:45 am
Amorphous ln-Sn-Zn-0
Upper Atrium/Hallway
Amorphous oxide semiconductors (AOSs) exhibit a rare combination of high optical transparency and high electron mobility surpassing that of amorphous silicon by orders of magnitude. Owing to the high electronegativity of oxygen anions and, hence, their strong interaction with metal cations, the network of metal-oxygen polyhedra is preserved on going from the crystalline to the amorphous state. Yet, variations in the oxygen coordination and distortions in the cation-anion chains alter the structure of valence and higher-energy conduction bands making it possible to tune the AOS properties. We employ first-principles density-functional calculations to investigate the structural and electronic properties of amorphous Zn-Sn-ln-0 and to determine how tensile strain affects the metal-oxygen bond lengths, bond angles, and coordination numbers in the oxide. Next, we identify the defect states responsible for the conductivity by calculating the atomic contributions to the valence and conduction band wave functions and characterize the defects structurally.
