2D Electronics, Layer by Layer
Two-dimensional materials now form the basis for a broad and rich field of research bristling with exciting possible applications from photonics to quantum computing and leading to discoveries of new phenomena due to the high customizability of the materials systems and interactions within them. Research in the Hollen lab focuses on understanding the role of defects, disorder, and interlayer interactions in determining the electronic properties of 2D crystals using scanning tunneling microscopy (STM). In this talk, I will describe how we observe degradation of 2D layers in air, control the disorder in 2D field-effect transistor devices, and understand the role of dynamics in determining a collective ground state. I will also highlight research directions undertaken by undergraduate students: creating nanometer-scale strain in a 2D sheet, designing protocols for making very sharp STM tips and understanding their electrostatic effects on imaging, creating programs for identifying defects in STM images, and extending our experimental tools to nanosecond time-resolution.
Shawna Hollen received her B.A. in physics from Occidental College in 2005, and her Ph.D. in physics from Brown University in 2013. For her Ph.D. work, she studied localized Cooper pairs near the quantum superconductor-insulator transition in the research group of Prof. James Valles. She did her postdoctoral work in the groups of Profs. Jay Gupta and Ezekiel Johnston-Halperin at the Center for Emergent Materials at the Ohio State University (2012-2015). There, she studied surface states and functionalization of ultra-high vacuum grown graphene islands with scanning tunneling microscopy (STM) and developed tools for coupling electrical transport measurements with local probes, such as STM. She joined the physics faculty at University of New Hampshire as an Assistant Professor in 2015.