EAS Young Alumni Lecture

Zakaria (Zak) Al Balushi will deliver the EAS Young Alumni Lecture on Wednesday, October 14, 2026 at 4 pm. Join the Division of Engineering and Applied Science for this special event and enjoy light refreshments beginning at 3:45 pm. Zak is associate professor of Materials Science and Engineering at University of California, Berkeley. Prior to his position at UC Berkeley, Zak was a Resnick Prize Fellow in Applied Physics and Materials Science and a NSF Alliances for Graduate Education and the Professoriate (AGEP) Fellow, both at Caltech.

Wednesday, October 14, 2026

Hartley Memorial Seminar Room, 106 Spalding

4 pm

Light refreshments available at 3:45 pm

Scalable Synthesis Routes to Low-Dimensional Materials for Next Generation Devices

Zak Al Balushi

Associate Professor of Materials Science and Engineering at University of California, Berkeley

Faculty Scientist at Lawrence Berkeley National Laboratory

Abstract

Low-dimensional materials, from atomically thin semiconductors to nanowires, offer properties unattainable in their bulk counterparts, yet their scalable synthesis and direct integration into functional devices remain significant challenges. This talk will show how deliberate control over precursor chemistry and processing can close that gap. Using single-source organosulfur precursors derived from dithioacids, we achieve wafer-scale, conformal growth of continuous mono- to few-layer metal sulfides, demonstrated across multiple polytypes. In situ spectroscopy and microscopy, reactive molecular dynamics, and density functional theory reveal how precursor chemistry controls crystallization, thickness, grain size, and defect formation. The reactive intermediate further enables substrate-selective growth, seed-free integration of atomic-layer-deposited dielectrics, transfer-free superlattice fabrication, and substitutional doping through precursor co-formulation, and the resulting films support reliable field-effect transistors and vertical memristors exhibiting nanosecond spike-timing-dependent plasticity. The same precursor-level thinking extends naturally to the metal-organic chemical vapor deposition of transition metal dichalcogenides, where tailored gas-phase chemistries and phosphorus-based passivation of silicon surfaces steer nucleation and interface formation, bringing 2D channels a step closer to direct integration with advanced transistor architectures.

While chemistry governs how these materials grow, their geometry can also be sculpted in the solid state. I will introduce a dry-release thermomechanical nanomolding platform for template-defined nanostructure arrays, in which lithographically defined silicon molds are filled by solid-state deformation of a metal feedstock and then selectively removed in a single dry-etch step. The process yields large-area, freestanding nanowire arrays with aspect ratios up to 43, demonstrated for aluminum and extended to indium, tin, zinc, silver, gold, and copper, as well as to complex three-dimensional geometries. Transmission Kikuchi diffraction, selected-area electron diffraction, and synchrotron X-ray nanodiffraction confirm that the wires are predominantly single-crystalline and non-epitaxial with respect to the feedstock, adopting at least two distinct growth directions, [110] and [100]. Monochromated electron energy-loss spectroscopy, corroborated by finite-difference time-domain simulations, reveals length-tunable longitudinal Fabry-Pérot plasmon modes with resonance energies as low as 75 meV, positioning ordered aluminum nanoantenna arrays as a scalable platform for mid-infrared nanophotonics. Together, these efforts illustrate how coupling materials design with template-directed processing delivers manufacturable low-dimensional materials for future electronics and photonics.

Biography

Zak Al Balushi is an associate professor with tenure in the department of Materials Science and Engineering at University of California, Berkeley, and a faculty scientist in the Materials Science Division at the Lawrence Berkeley National Laboratory. Zakaria received his B.S. (2011), M.S. (2012) in Engineering Science and his Ph.D. (2017) in Materials Science and Engineering all from The Pennsylvania State University. His early work focused on integration and fabrication of silicon nanowire devices, then on the growth of group-III nitride semiconductors, in situ metrology during MOCVD growth, epitaxial graphene and the discovery and characterization of unconventional low-dimensional materials and heterostructures. Prior to his appointment at the University of California, Berkeley, he held two postdoctoral fellowships: the Resnick Prize Fellowship in Applied Physics and Materials Science and the NSF Alliances for Graduate Education and the Professoriate (AGEP) Fellowship both at the California Institute of Technology under the supervision of Professor Harry Atwater. At the University of California, Berkeley, his research group continues to expand in this area and beyond, creating new synthesis and integration schemes for emerging low-dimensional materials. He is currently serving on the editorial board of Communications Materials, is an elected executive committee member for the American Association for Crystal Growth and recently named "Four rising stars who are reshaping nanoscience" by Nature [Nature 608, S12-S13 (2022)]. He is also a SK Hynix Faculty Fellow, Society of Hellman Fellow, a CIFAR Azrieli Global Scholar in Quantum Materials and a recipient of the NSF CAREER and Micron Corporation Early Career Awards in 2022.