Non-technical abstract. The focus of this research project is an experimental study of artificially synthesized heterostructures based on novel semiconducting materials combined in a single device. When certain materials are brought together in physical contact, the contact can exhibit new interesting properties, different from the properties of the original materials, including, for instance, high electrical conductivity, with electrons flowing freely, without being captured by defects. Such properties can be advantageous for future electronic and photonic devices, such as transistors, light-emitting diodes and solar cells. These heterostructures can also be used to study the fundamental intrinsic properties of semiconductors, not masked by defects. The types of materials that can be combined in functional van der Waals heterostructures are organic semiconductors, inorganic layered materials with inert (van der Waals) surfaces and organic polymers. Research on emergent electronic materials, where fundamental physics and applied studies overlap, represents an excellent opportunity for students to learn about current developments in semiconductor physics and technology, acquire modern research skills and become prepared for a successful career in science and engineering. Technical Abstract. The physics of charge carrier transport at van der Waals heterointerfaces, in particular interfaces between non-conjugated fluoropolymers with incorporated polar functional groups and novel semiconductors, including organic molecular crystals and layered inorganic nanomaterials (monolayer materials), is the focus of this project. Understanding the mechanisms of induced surface conductivity and 'trap healing' effect, recently observed at such interfaces, is the main thrust of the activity. Several interesting transport phenomena emerging at this kind of interfaces, including suppressed carrier trapping and low-noise conduction, leading to the observation of a high-resolution Hall effect, enable the research team to experimentally access the intrinsic (trap-free) charge transport regime in a variety of organic semiconductors and novel layered inorganic nanomaterials. Low-temperature transport and Hall effect measurements, combined with a photo-current excitation spectroscopy, are used to study these interfaces. Implementation of the project is expected to result in the development of novel semiconductor heterostructures, stimulate synthesis and applications of novel functional polymers, lead to new methodologies of high-precision Hall effect measurements, especially important for emergent solution-processed semiconductors, and more broadly contribute to a better understanding of electronic and optical properties of novel materials. The interdisciplinary nature of this project provides excellent educational, human resource and outreach opportunities, including training of students and postdocs.
|Effective start/end date||8/1/15 → 7/31/18|
- National Science Foundation (National Science Foundation (NSF))