Probing the Atomic Origins of Electronic States in Low Dimensional Materials and Interfaces
Abstract
During this three-year grant, we have published five manuscripts, given nine conference talks and invited seminars, and been awarded six awards in recognition of my group's research. Our main work has focused on studying doping and strain in 2D materials and the impact that these structures have on the electronic properties of 2D materials and devices. As part of this work, we developed electron microscopy methods to measure picometer-scale displacements of individual atoms near point defects in 2D materials. Using this approach, we demonstrated methods to measure atomic displacements with 0.3 picometer precision, representing more than an order of magnitude improvement over conventional imaging of 2D materials with aberration-corrected STEM (C.-H. Lee et al., Nano Letters 2020). This new level of precision allowed us to uncover previously unseen features in the strain field around vacancies in WSe2-2xTe2x, including atomic-scale, radial strain oscillations around a vacancy, a phenomena first predicted in the 1950s. These results are significant because they point to methods to detect localized electronic rearrangements through high-precision electron microscopy, and because they demonstrate the coupling between strain and electronic charge at defects in 2D systems. In addition to the above research focus, we also completed four collaborative projects in nanoelectronic materials and devices. This work includes the development of a new fabrication method using graphene etch stops (J Son et al., Nature Communications 2018) to produce complex integrated 3D device structures with high electrical mobilities the highest ever reported for graphene at the time of our publication. In addition, our collaborative project on strained 2D materials (Y. Zhang et al., Nano Letters 2018) demonstrates spatially periodic strain tuning of up to 2 percent in graphene and MoS2 using arrays.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 15, 2020
- Accession Number
- AD1110223
Entities
People
- Pinshane Huang
Organizations
- University of Illinois Urbana–Champaign