Excitons and exciton-polaritons in novel organic-inorganic hybrids with sub-nano II-VI or III-V layers
Abstract
Translational symmetry ensures phase coherency of a physical process among different units of a crystal, and thus produces collective effects beyond the sum of the units. Any significant physical and/or chemical fluctuation, which typically exists in a semiconductor alloy or self-assembled or artificially grown nanostructure array, would hinder our ability to study and use the collective behavior relying on this coherency (e.g., free excitons in a crystal). Man-made structures remain as one of the central interests since they were proposed by Esaki and Tsu in 1970. Unfortunately, man-made structures with genuine long-range order are rarely found in reality. Here a new family of inorganic-organic hybrid nanostructures provides us a unique opportunity to explore the coherent phenomena in man-made structures. These self-assembled hybrid structures are ultra-thin slabs or atomic chains of II-VI semiconductors interconnected or coordinated by small organic molecules, exhibiting very high degree of structural perfectness as good as a typical binary semiconductor. Besides the structural perfectness, our exploration on a few selected members has already revealed a number of extraordinary properties (e.g., exceedingly strong exciton-polariton absorption, zero thermal expansion). By varying either the inorganic or organic component, we can tune the coupling between the inorganic units to achieve quasi-1-D, quasi-2-D, and 3-D super-structures with tailored material properties for different basic research interests and potential applications (e.g., room temperature exciton-polariton condensation, high efficiency UV emission and detection, p-type transparent conducting material). Furthermore, sub-nanometer scale inorganic units allow exploring physics in reduced dimensionalities to their practically achievable limits. This project focus on three areas: (1) understanding the basic electronic and optical properties of the hybrids, focusing on the free exciton and exciton-polariton phenomena, (2) tuning the electronic coupling between the inorganic units by changing both the inorganic elements and the length of connecting organic molecules, and (3) chemical synthesis of the III-V counterparts of the reported II-VI based hybrids
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810079
Entities
People
- Yong Zhang
Organizations
- Army Contracting Command
- United States Army
- University of North Carolina at Chapel Hill