Engineering Strain and Dimensionality of Perovskite Chalcogenide Thin Films and Heterostructures
Abstract
Transition Metal Perovksite Chalcogenides (TMPCs) are a new class of complex chalcogenides with broad structural and chemical tunability. The highly degenerate d-bands of the transition metal allows for large density of states conduction band, and hence the possibility of achieving large absorption coefficient, high electron density. The small electronegativity difference between the cations and the chalcogen allows for smaller band gap, and higher phonon limited mobility to greater covalency of TMPCs over the equivalent perovskite oxides. This offers a unique opportunity for TMPC semiconductors to demonstrate large density of states, while maintaining high carrier mobility. Further, these materials are responsive in the visible to infrared part of the electromagnetic spectrum making them highly relevant for several electronic and optoelectronic applications. This research effort is aimed at heteroepitaxial thin film growth of these ternary compounds and using this growth method to demonstrate strain and dimensionality engineering of physical properties of semiconducting TMPCs. To achieve this goal, (i) we will use pulsed laser deposition with chalcogen cracker cells to achieve stoichiometric, high quality epitaxial thin films of TMPCs; (ii) we will use a broad range of structural and chemical characterization probes to clarify the role of defects in limiting the physical properties; and finally, (iii) demonstrate tunable optical and electrical properties via strain and dimensionality engineering of TMPCs and related phases. A deep and fundamental understanding of the range of tunability in their properties, especially in the film form, is crucial to develop next generation electronic and optoelectronic devices. These functional materials and devices will enable next generation military and civilian applications in critical Army technologies such as sensing, threat detection, surveillance, energy conversion, information processing. Scientifically, these studies for the basis for future realization of chemically diverse epitaxial heterostructures of oxides and chalcogenides and ensuing phenomenological and technological opportunities for electronics and photonics.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 11, 2019
- Source ID
- W911NF1910137
Entities
People
- Jayakanth Ravichandran
Organizations
- Army Contracting Command
- United States Army
- University of Southern California