Research

Dielectric Constant Imaging by Electric Force Microscopy Combined with Finite Element Method (COMSOL Multiphysics)

Our group explores the nanoscale dielectric landscape of low-dimensional materials by combining electric force microscopy with finite element simulations. This approach enables quantitative mapping of local permittivity (κ) with nanometer precision, offering critical insights into charge polarization, electrostatic screening, and local field distributions. By visualizing dielectric properties at the single-nanostructure level, we aim to design and engineer next-generation high-κ materials for advanced nanoelectronic and quantum devices, contributing to the fundamental understanding of dielectric behavior in emerging 2D systems.

Kelvin Probe Force Microscopy under Gate-Bias Sweeps for Nanoscale Charge-Trapping Imaging

We visualize nanoscale charge trapping in locally strained bubble structures of 2D materials by combining Kelvin probe force microscopy with gate-bias sweeps. This approach reveals how local strain distorts the energy band structure, induces charge-trap states, and governs their trap density, spatial distribution, and capture–emission dynamics. As a result, key reliability issues in 2D-material-based devices—such as hysteresis, threshold drift, and retention loss—become directly measurable and tunable. By constructing pixel-level hysteresis maps of the local electrostatic potential (EF-hysteresis maps), we correlate strain profiles with trap behavior, enabling the design of cleaner interfaces and optimized device architectures for stable transistors, sensors, and neuromorphic elements.

Gate-Swept Conductive AFM for Local, Gate-Tunable Charge-Storage Memory

We use gate-swept conductive AFM to probe local charge-storage behavior in intrinsically trap-rich nanoscale structures, such as bubbles and other inhomogeneities in 2D materials. We exploit native charge trapping and de-trapping under gate modulation to obtain local transfer characteristics with nanometer-scale resolution, along with stable endurance and retention metrics. With this approach, we are developing a versatile workflow that can be applied to many material systems and directly used to guide device design, so that local charge-trapping phenomena in 2D materials can be harnessed to improve the performance and reliability of future memory, neuromorphic, and other charge-storage devices. 

Functional Probes for Nanoscale Mechanical & Opto-Electrical Applications

We engineer multifunctional SPM probes, from robust single-nanoparticle tips for contact-mode mechanics and on-chip nanolithography to nano-prism/NV tips that create ultra-small optical hot spots for near-field spectroscopy. Our methods are scalable and allow precise control of tip geometry, materials, and optical response, enabling reliable ANSOM/TERS signals and high-fidelity topography. With this platform we measure, write, and control at the nanoscale, advancing stiffness and charge mapping and on-chip patterning of functional layers. We also perform wavelength- and polarization-selective nanospectroscopy that supports device-oriented prototyping and scalable probe arrays for materials discovery.