Technology and applications of 2D materials in micro- and macroscale electronics

Abstract

Over the past 50 years, electronics has truly revolutionized our lives. Today, many everyday objects rely on electronic circuitry from gadgets such as wireless earbuds, smartphones and laptops to larger devices like household appliances and cars. However, the size range of electronic devices is still rather limited from the millimeter to meter scale. Being able to extend the reach of electronics from the size of a red blood cell to a skyscraper would enable new applications in many areas including energy production, entertainment, environmental sensing, and healthcare. 2D-materials, a new class of atomically thin materials with a variety of electric properties, are promising for such electronic systems with extreme dimension due to their flexibility and ease of integration. On the macroscopic side, electronics produced on thin films by roll-to-roll fabrication has great potential due to its high throughput and low production cost. Towards this end, this thesis explores the transfer of 2D-materials onto flexible EVA/PET substrates with hot roll lamination and electrochemical delamination using a custom designed roll-to-roll setup. The transfer process is characterized in detail and the lamination of multiple 2D material layers is demonstrated. As exemplary large-scale electronics application, a flexible solar cell with graphene transparent electrode is discussed. On the microscopic side, this thesis presents a 60x60 [mu]m² microsystem platform called synthetic cells or SynCells. This platform offers a variety of building blocks such as chemical sensors and transistors based on molybdenum disulfide, passive germanium timers, iron magnets for actuation, as well as gallium nitride LEDs and solar cells for communication and energy harvesting. Several system-level applications of SynCells are explored such as sensing in a microfluidic channel or spray-coating SynCells on arbitrary surfaces.