CAREER: Tailoring van der Waals Ferroelectricity in 2D Layered Semiconductors

Nontechnical description

The relentless growth of data-driven computing and artificial intelligence is pushing conventional microelectronics to their limits, necessitating new technologies that reduce power consumption and latency. This project explores a new family of atomically thin ferroelectric semiconductors—materials that maintain a reversible electric polarization—to advance high-performance logic devices, efficient memory architectures, and integrated nonlinear photonics.

By developing robust synthesis techniques and controlling atomic-scale features within semiconductor materials and interfaces, the research aims to enhance next-generation electronic devices. A key aspect is understanding how ferroelectric polarization switches in these materials, measuring the speed of this switching process, and observing its impact on electronic properties.

To inspire future engineers and address the growing needs of the semiconductor industry, the educational outreach component targets middle school students, igniting their curiosity about the quantum origins of everyday phenomena. This includes workshops for middle school teachers, providing them with lessons and supplies to demonstrate two-dimensional semiconductor physics in the classroom.

The project also engages high school interns in building new software tools for open-source two-dimensional semiconductor metrology. Technical description

The research focuses on rhombohedral transition metal dichalcogenides, such as tungsten disulfide and tungsten diselenide, which exhibit van der Waals ferroelectricity due to non-centrosymmetric interlayer stacking configurations. These materials have recently gained interest for their reported enhancements in carrier mobility, their high-speed, high-fatigue-resistance switching properties, and their efficient nonlinear optical frequency doubling.

This project addresses the challenge of synthesizing these materials and understanding their ferroelectric and charge transport properties. The core scientific objectives include: (1) synthesizing molybdenum and tungsten-based rhombohedral transition metal dichalcogenides as large single crystals on standard semiconductor substrates with control over substitutional doping via chemical vapor deposition; (2) applying nanoscale microcopy and spectroscopy with high spatial and temporal resolution to study ferroelectric domain dynamics and to measure and optimize switching speeds; and (3) measuring electronic transport in devices to characterize how ferroelectric polarization affects charge transport through multilayer domain configurations and interactions with dopants.

These studies aim to improve integration potential, switching speed, and charge transport in ferroelectric two-dimensional semiconductors, influencing the design of future memory and logic-in-memory devices. The research aligns with the goals of the Electronic and Photonic Materials program by advancing the understanding of materials with reduced dimensionality, exploring fundamental mechanisms at the atomic level, and potentially offering new paradigms in computing and communications.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.