Changhwan Choi

The development of bioinspired electronic devices that can mimic the biological synapses is an essential step towards the development of efficient neuromorphic systems to simulate the functions of the human brain. Among various materials that can be utilized to attain electronic synapses, the existing semiconductor industry-compatible conventional materials are more favorable due to their low cost, easy fabrication and reliable switching properties. In this work, atomic layer deposited HfO2-base

Abstract A two terminal semiconducting device like a memristor is indispensable to emulate the function of synapse in the working memory. The analog switching characteristics of memristor play a vital role in the emulation of biological synapses. The application of consecutive voltage sweeps or pulses (action potentials) changes the conductivity of the memristor which is considered as the fundamental cause of the synaptic plasticity. In this study, a neuromorphic device using an in-situ growth o

Abstract Carbon‐based electronic devices are suitable candidates for bioinspired electronics due to their low cost, eco‐friendliness, mechanical flexibility, and compatibility with complementary metal‐oxide‐semiconductor technology. New types of materials such as graphene quantum dots (GQDs) have attracted attention in the search for new applications beyond solar cells and energy harvesting due to their superior properties such as elevated photoluminescence, high chemical inertness, and excellen

Abstract Single transducer with humidity sensing materials has limitations in both range and sensitivity, which cannot be used to detect the full range of humidity with consistent sensitivity. To enlarge range and improve sensitivity in the all range relative humidity (RH), we propose a highly sensitive and full range detectable humidity sensor based on multiple inter-digital transducer (IDT) electrodes connected in series with poly(3,4-ethylenedioxythiophene) doped poly (styrene sulfonate) anio

Neuromorphic computing has garnered significant attention because it can overcome the limitations of the current von-Neumann computing system. Analog synaptic devices are essential for realizing hardware-based artificial neuromorphic devices; however, only a few systematic studies in terms of both synaptic materials and device structures have been conducted so far, and thus, further research is required in this direction. In this study, we demonstrate the synaptic characteristics of a ferroelect

Abstract Transition metal carbides, called MXenes, can be used for MXene‐based unique electronic devices such as new types of batteries, energy storage devices, and supercapacitors, where MXene is used as an electrode. The unique surface properties of MXene and 2D structure can be further applied to the new electronic devices. In this paper, the unique insulating properties of partially oxidized MXene (Ti 3 C 2 T x ) sheets are utilized for memory storage and electronic synapse applications. The

Abstract Nanocomposites based on biomaterials are promising candidates for emerging green‐ electronics benefiting from environment‐friendly, renewable, biocompatible, and biodegradable resources for sustainable research and development. Especially, the application of biocomposites‐based memristor for simulating artificial synapses called bio‐memristor has further facilitated the progress of ecologically benign bioelectronics. In this study, the authors present that the environment‐friendly nanoc

Abstract We demonstrate inherent biorealistic synaptic plasticity functions in the Pt/n-ZnO/SiO 2– x /Pt heterostructures, where the n-ZnO semiconductor is geometrically cone-shaped in the size of a few nanometers. The synaptic functions were achieved within a two-terminal, electroforming-free, and low-power rectifying diode-like resistive switching device. The important rate-dependent synaptic functions, such as the nonlinear transient conduction behavior, short- and long-term plasticity, paire

Abstract We performed various pulse measurements on an atomic layer deposited (ALD) HfO 2 -based resistive switching random access memory (RRAM) device and investigated its electronic synaptic characteristics. Unlike requirements for RRAM device application, to achieve the multi-state conductance changes required for the synaptic device, we employed additional sputtered TaO x thin film formation on the ALD HfO 2 switching medium, which leads to engineering the concentration of oxygen vacancies a

We report the dependence of the thickness of amorphous boron nitride (a-BN) on the characteristics of conductive bridge random access memory (CBRAM) structured with the Ag/a-BN/Pt stacking sequence. The a-BN thin film layers of three different thicknesses of 5.5, 11, and 21.5 nm were prepared by the sputtering deposition. Depending on the thickness of the a-BN layer, the devices are found to be in either low-resistance state (LRS) or high-resistance state (HRS) prior to any consecutive switching