Research 03 · Advanced memory devices

Store a stateShape the future

EPID develops memory devices in which polarization, quantum tunneling, field-effect control, and electrochemical ion motion become programmable physical states. We connect materials and interfaces to low-power computing, adaptive electronics, and sustainable systems.

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State variablesPolarization · Barrier · Threshold · Conductance

Overview

Program matterPreserve information

Our research spans charge-free polarization switching, tunneling barriers, transistor memory, and ion-driven resistance. Across every platform, we control the active material, its interfaces, and the electrical history that defines a reliable state.

Ferroelectric memory

We engineer switchable polarization, interfaces, and capacitor stacks for fast, low-voltage, and nonvolatile information storage.

Ferroelectric tunnel junction

Nanometer-scale ferroelectric barriers translate polarization reversal into a large tunneling electroresistance window.

Ferroelectric FET

Ferroelectric gate stacks program the channel threshold, combining memory and transistor gain in a scalable device.

Biodegradable electrochemical RRAM

Transient materials and electrochemical switching create programmable resistance for sustainable, implantable, and disposable systems.

01 · Ferroelectric memory

Switch polarizationRetain the state

Metal–ferroelectric–metal and metal–ferroelectric–insulator stacks store information in two stable polarization orientations. We study phase formation, electrode symmetry, depolarization field, domain dynamics, and defect-mediated wake-up or fatigue.

HZO thin-film synthesis, nanolaminates, and phase stabilization
Interface, oxygen-reservoir electrode, and vacancy engineering
Pulse switching, domain kinetics, endurance, and retention
Scalable capacitor cells and array-relevant operation

Three-dimensional cutaway of a vertical HZO ferroelectric memory capacitor with nanolaminate polarization domains and an oxygen-reservoir interface — Nonvolatile polarization states in a ferroelectric capacitor stack

Three-dimensional cutaway of a crossbar ferroelectric tunnel junction with an ultrathin HZO and zirconium oxide bilayer barrier — Polarization-controlled tunneling electroresistance

02 · Ferroelectric tunnel junction

Reorient the dipolesReshape the barrier

In an FTJ, polarization changes the electrostatic potential across an ultrathin barrier. The resulting tunneling electroresistance provides nondestructive readout, compact two-terminal cells, and analog conductance for in-memory computation.

Ultrathin HZO and ZrO₂ bilayer barrier formation
Asymmetric electrodes and band-alignment engineering
High ON/OFF and tunneling electroresistance ratios
Multilevel switching and synaptic weight modulation

03 · Ferroelectric FET

Program the gateControl the channel

A FeFET stores polarization in the gate stack and reads it as a persistent threshold-voltage shift. We co-optimize the ferroelectric, interfacial dielectric, channel, and pulse scheme for a wide and stable memory window.

MFIS and MFMIS HZO gate-stack design
Graphene interlayers, interfaces, and charge-injection control
Threshold-voltage window, variability, and disturb
Logic-compatible processing and embedded arrays

Three-dimensional cutaway of a high-endurance HZO ferroelectric FET with a graphene interlayer, interfacial dielectric, and programmable channel — Polarization-programmed threshold voltage in a ferroelectric FET

Three-dimensional cutaway of a biodegradable W, magnesium, PVP, magnesium, and chitosan RRAM showing ion migration and a reversible conductive filament — Reversible electrochemical filament formation in a transient stack

04 · Biodegradable electrochemical RRAM

Write with ionsDisappear by design

Electrochemical metallization forms and dissolves a nanoscale conductive path inside a biodegradable switching medium. Our W/Mg/PVP/Mg platform on chitosan combines nonvolatile or analog resistance with a controlled physical lifetime.

PVP biopolymer, Mg electrodes, and chitosan substrates
Mg-ion transport, filament nucleation, and dissolution
Low-voltage binary and analog resistive switching
Transient sensors, implantable systems, and eco-friendly electronics

Materials to memory

Measure every stateExplain every transition

Electrical behavior becomes meaningful only when it is connected to structure, chemistry, interfaces, and time-dependent degradation.

Polarization

P–E, PUND, switching-current, and pulse measurements separate genuine polarization from leakage and trapping.

Transport

I–V–T, area scaling, and barrier analysis identify tunneling, injection, filamentary, and interface-limited conduction.

Structure

XRD, AFM, XPS, and TEM connect phase, texture, chemistry, thickness, and interfaces to electrical behavior.

Reliability

Endurance, retention, imprint, wake-up, fatigue, variability, and environmental degradation define the usable window.

Research direction

From a stable bit to an integrated function

Materials→Interfaces→Devices→Arrays→Intelligent systems

Join EPID

Build memory with new physics

We welcome students and researchers interested in ferroelectric materials, tunnel junctions, FeFETs, electrochemical RRAM, transient electronics, and integrated memory systems.

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