Arizona State University
David J. Smith
Department of Physics
College of Liberal Arts & Sciences


     Our research interests include oxide and semiconductor heterostructures, magnetic thin films and multilayers, and many types of nanostructures. Semiconductor systems of interest include ternary and quaternary Group III nitride alloys for light-emitting diodes and high power devices, and II-VI/III- alloys as photodetectors, especially for solar-cell applications. Magnetic materials being studied include magnetic tunnel junctions, which are based on ferromagnet-insulator-ferromagnet combinations, that have promising applications for non-volatile, high-storage-density recording media. Aberration-corrected electron microscopy and spectrum imaging is being used to locate and identify atomic species, while off-axis electron holography is being used to investigate the magnetization behavior and fringing fields associated with patterned nanostructures in addition to studies of semiconductor pn junctions and piezoelectric fields in thin films and nanowires.

Nanoscale Imaging of Electromagnetic Fields
Phase maps showing domain structure and perpendicular magnetic anisotropy in CoFe/Pd multilayers (Desai Zhang)
Reconstructed phase image of Ge/lithiated-Ge core/shell nanowire (Zhaofeng Gan)
Integration of Oxide-Semiconductor Heterostructures
Anti-phase boundary at strontium titanate/silicon interface (HsinWei Wu)
Quasi-2DEG at Oxide-Oxide interfaces
Cross-section image of epitaxial alumina/strontium titanate interface (Sirong Lu)
Investigation of Heterovalent Semiconductor Interfaces
Quantification of strain across CdTe/InSb hetero-interface (Jing Lu)
Failure Mechanisms for III-Nitride Devices
Reconstructed phase image showing gate region of GaN/AlGaN HEMT device (Thomas McConkie)
Towards Improved Hg-based Infrared Detectors
Cross-section electron micrograph showing CdTe/ZnTe/Si(211) interface (Majid Vaghayenegar)
Investigating novel 2D dichalcogenides
Cross-section image showing epitaxial tin diselenide film on GaAs substrate (Brian Tracy)