CAREER: Semiconducting Delafossite Structures for Transparent Conducting Coating

Iowa State University, Ames IA

Investigators

Abstract

This CAREER project systematically explores the electrical and optical properties of cation-substituted delafossite structures. The electrical and optical properties of AgInO2 can be attributed to certain unique features of the delafossite structure; it consists of a two-dimensional array of monovalent A-atoms (Cu, Ag, Pd, or Pt) sandwiched between layers of B 3+ O6 octahedra. It is the linearly coordinated O-A-O structure in these materials that is the key to their conduction mechanism. The experimental objective of this project is to determine crystal chemical relationships that influence orbital overlap between metallic A-atoms and the crystal field splitting of 3d or 4d states. With cationic substitutions on the A- and B-sites, it may be possible to manipulate the A-A and O-A-O distances in the delafossite structure. It is expected that these modifications to the structure will be manifested in variations in the conductivity, mobility, band gap, and optical transmission in the visible spectrum. The research themes will be related to the K-12 classroom with the help of a collaborating K-12 science teacher. The collaborator will work with the research group during the summer, thereby, receiving practical experience in materials science. He or she will use this knowledge in the classroom in the following school semester. In addition, a summer science program will be initiated at a local residential facility for children with emotional and behavioral disorders. A combination of hands-on experiments with materials, one-on-one instruction, and an internet-based scanning electron microscope (SEM) will be used to capture the children's attention and stimulate their interest in science. %%% The project addresses fundamental research issues in a topical area of materials science having high technological relevance. The scope of the project will expose students to challenges in materials synthesis, processing, and characterization. An important feature of the project is the strong emphasis on education, and the integration of research and education. ***