Controlled Synthesis, Processing, and Applications of Structural and Functional Nanomaterials: Nanocomposites & 2D Materials
Sponsored by: ACerS Basic Science Division, ACerS Electronics Division, ACerS Engineering Ceramics Division
Program Organizers: Haitao Zhang, University of North Carolina at Charlotte; Gurpreet Singh, Kansas State University; Kathy Lu, University of Alabama Birmingham; Edward Gorzkowski, Naval Research Laboratory; Jian Shi, Rensselear Polytechnich University; Michael Naguib, Tulane University; Sanjay Mathur, University of Cologne
Tuesday 2:00 PM
October 19, 2021
Room: B240/241
Location: Greater Columbus Convention Center
Session Chair: Sanjay Mathur, University of Cologne; Haitao Zhang, University of North Carolina at Charlotte
2:00 PM Invited
2d Crystalline Donors and Acceptors: Modulation Doping in Atomically-thin Heterostructures: Erik Henriksen1; 1Washington University in St. Louis
a-RuCl3 is a layered antiferromagnetic Mott insulator widely thought to host a close relative of the Kitaev quantum spin liquid state. It can be exfoliated down to monolayer thicknesses and incorporated into van der Waals heterostructures along with graphene and myriad other atomically thin materials. Proximity of a-RuCl3 to graphene (and other materials) leads to a significant charge transfer between the two that, surprisingly, persists even when a thin insulating layer is inserted between them, a phenomenon analogous to modulation doping in epitaxially-grown semiconductors. This heralds a new method of charge control in van der Waals stacks: we envision the construction of layered devices with both p- and n-type doping to recapitulate modern computing technology in atomically thin materials. We illustrate this potential with evidence for ultra-sharp pn junctions.
2:30 PM
Thickness-dependent Piezoelectric Property of Two-dimensional Zinc Oxide Nanosheets with Unit Cell Resolution: Corey Carlos1; Yizhan Wang1; Jingyu Wang1; Jun Li1; Xudong Wang1; 1University of Wisconsin - Madison
Piezoelectric and semiconducting materials have drawn intense interest for their excellent potential to advance the field of wearable electronics and piezotronic devices. Moreover, two-dimensional (2D) nanomaterials, valued for their enhanced mechanical, electronic, and structural properties, have moved to the forefront of compliant electronic devices. Therefore, a thorough understanding of the size effects in piezoelectric semiconductors such as zinc-oxide (ZnO), is required at the nanoscale. We present a thickness-dependent study of the piezoelectric response of nanometer-thick 2D ZnO nanosheets (NS) grown via Ionic Layer Epitaxy (ILE) with unit cell precision. The size dependence of the piezoelectric effect within ZnO-NSs, is monitored in situ via piezo force microscopy (PFM). Using PFM, we illustrate the size effects of piezoelectric nanomaterials and its role in the polarization charge distribution across the surface of the 2D ZnO-NS for future piezotronic applications.
2:50 PM
Processing and Mechanical Properties of 3YSZ-Al2O3 Core-Shell Nanocomposite Ceramics: Kevin Anderson1; Benjamin Greenberg1; James Wollmershauser1; Boris Feigelson1; 1U.S. Naval Research Laboratory
Through the mechanism of transformation toughening, zirconia with the tetragonal crystal structure is among the toughest ceramics (~5-10 MPa√m) while only being moderately hard (Hv ~13 GPa). Conversely, alumina is one of the hardest oxides (Hv ~18-20 GPa) with relatively poor toughness (~3 MPa√m). In an effort to enhance hardness while maintaining toughness, novel zirconia toughened alumina (ZTA) composites were synthesized by coating tetragonal phase 3 mol% yttria stabilized zirconia with alumina via particle atomic layer deposition (pALD) and subsequently densified using Environmentally Controlled – Pressure Assisted Sintering (EC-PAS). EC-PAS utilizes creation and preservation of pristine nanoparticle surfaces throughout the sintering process, applied pressure (<2 GPa), and low temperature (< 0.5 Tm) to achieve densification with negligible grain growth. Fully dense, 3YSZ-Al2O3 core-shell nanocomposites with hardnesses as high as 17 GPa and toughnesses as high as 10 MPa√m were created and characterized with XRD, SEM, and Vickers microindentation.