Doowon Lee

• Doctor of Engineering
• Professor (Assistant) at Kongju National University

In this paper, we optimized IGZO/Ag/IGZO (IAI) multilayer films by post-rapid thermal annealing (RTA) to enhance the electrical conductivity and optical transmittance in visible wavelengths for solar cell applications. Our optimized device showed an average transmittance of 85% in the visible range, with a lowest sheet resistance of 6.03 Ω/□ when a...

We present a transparent memristor with a rough-surface (RS) bottom electrode (BE) with enhanced performance and reliability for a gasistor, which is a gas sensor plus a memristor, and its application in this paper. The transparent memristor, with an RS BE, exhibited low forming voltages (0.8 V) and a stable resistive switching behavior, with high...

Designing a transparent carbon nanotube (CNT) gas sensor for nitrogen dioxide (NO2) detection at room temperature (RT), which is unaffected by humidity, is a critical challenge in various technologies. To solve this issue, a filament‐based memristor heater (MH) embedded low‐power CNT gas sensor is proposed to address humidity‐related issues, and dy...

In this paper, we studied the post-treatment effect in order to optimize the optical and electrical properties of the IZO transparent conductive oxide (TCO). We used the rapid thermal annealing (RTA) process, which provides direct thermal energy, and the micro-wave treatment (MWT) process, which provides vibrational energy of particles among the va...

Memristor-based gas sensors (gas sensor + memristor, gasistor) have gained popularity due to their high response characteristics and ability to operate at room temperature (RT). In this paper, N-[3-(Trimethoxysilyl)propyl]ethylenediamine (en-APTAS), a commonly used membrane for NOx gas sensors, is applied in the gasistor with carbon nanotubes (CNTs...

Low-power-consumption gas sensors are crucial for diverse applications, including environmental monitoring and portable Internet of Things (IoT) systems. However, the desorption and adsorption characteristics of conventional metal oxide-based gas sensors require supplementary equipment, such as heaters, which is not optimal for low-power IoT monito...

In aerospace applications, SiOx deposition on perovskite solar cells makes them more stable. However, the reflectance of the light changes and the current density decreases can lower the efficiency of the solar cell. The thickness of the perovskite material, ETL, and HTL must be re-optimized, and testing the number of cases experimentally takes a l...

BN-based resistive random-access memory (RRAM) has emerged as a potential candidate for non-volatile memory (NVM) in aerospace applications, offering high thermal conductivity, excellent mechanical, and chemical stability, low power consumption, high density, and reliability. However, the presence of defects and trap states in BN-based RRAM can lim...

Memristor-based gas sensors (gasistors) have been considered as the most promising candidate for detecting NO gas suitable for neural network (NN) analysis. In this work, in order to solve an overfitting issue arising from the training data when using a single gasistor, which degrades the accuracy of NN, we here propose a metal-insulator-silicon (M...

Antireflection coatings (ARCs) with an indium thin oxide (ITO) layer on silicon heterojunction solar cells (SHJ) have garnered significant attention, which is due to their potential for increasing current density (Jsc) and enhancing reliability. We propose an additional tungsten trioxide (WO3) layer on the ITO/Si structure in this paper in order to...

In this paper, we investigate the effects of aluminum oxide (Al2O3) antireflection coating (ARC) on silicon heterojunction (SHJ) solar cells. Comprehensive ARCs simulation with Al2O3/ITO/c-Si structure is carried out and the feasibility to improve the short circuit current density (JSC) is demonstrated. Based on the simulation results, we apply Al2...

One of the major challenges with a nitric oxide (NO) gas sensor is the development of a facile and robust room temperature gas sensor for fast recovery and high response in an NO ambient, especially below ppb-level. In order to detect an NO gas in ppb-level, a Zr3N4 based gasistor with very sensitive conducting filaments was investigated. The propo...

Patterning an insulator to make electrical contact between the front electrode and the emitter is essential in solar cells, resulting in an increase in manufacturing cost. In this paper, conducting filaments (CFs) are applied to the silicon heterojunction (SHJ) solar cell with an SiOx/ITO structure for the first time. The self-assembled CFs in SiOx...

Oxygen (O2) sensing in trace amounts and mixed gas is essential in many types of industries. Semiconductor sensors have proven to be invaluable tools for the O2 measurements in a wide concentration range, but the sensors are only able to quantify O2 in a concentration range of subppm, thus far, especially in mixed gas. We present in this paper a ne...

In this study, we present a correlation between the resistive switching (RS) characteristics and the traps of Zr3N2, which is based resistive random-access memory (RRAM) with a TiN barrier electrode, in order to identify the RS mechanism of the trap-based RRAM devices. First, gradual asymmetrical RS properties were discovered in the RS test, which...

In this paper, we present the high sensitivity of an isopropyl alcohol gas sensor, which is based on a memristor device that is operated at room temperature. We proposed the SnO2-based memristor to detect isopropyl alcohol and demonstrated the change in the current of the SnO2-based memristor that is monitored in real time depending on concentratio...

Charge-trap based resistive switching (RS) has attracted attention in the resistive random-access memory (RRAM) industry due to its gradual RS behavior for multi-level and synaptic applications. In this work, in order to lower the operating current level closely related to device’s degradation, we applied a hydrogen passivation to Zr <sub xmlns:mml...

Zinc-doped indium oxide (IZO)+ tin-doped indium oxide (ITO) is proposed in this study as a double-layered transparent conductive oxide (TCO) for the application of silicon heterojunction (SHJ) solar cells. IZO is consecutively deposited via radio frequency sputtering at room temperature. The electrical and optical characteristics of IZO are examine...

The electrical and optical properties of IGZO-based transparent conductive oxide (TCO), fabricated by reactive-sputtering, are optimized using post microwave treatment (MWT), not rapid temperature annealing (RTA), for silicon solar cell. Compared to the sheet resistance and transmittance of IGZO-based TCO after RTA and MWT, we observed a transmitta...

This work reports forming free/self-rectifying resistive switching characteristics and dependency of the top electrode (TE) of a crystalline HfO2-based resistive switching memory device. In the memory cells, nonlinear bipolar resistive switching characteristics, i.e., an asymmetric current-voltage curve like the Schottky diode, was observed. In add...

In this study, we investigated the self-rectifying characteristics of p-Si/O-doped ZrN/TiN structures in order to overcome a disturbance between neighboring cells in array structures. The proposed device shows a nonlinear selection characteristic and a Schottky diode property in the positive bias region. We also observed the rectifying region withi...

In this study, we present a self-rectifying resistive switching property observed in Ti/Zr3N2/p-Si and Ti/Zr2N/p-Si metal-insulator-semiconductor (MIS) capacitors for array applications. Compared to the Zr2N film, the Zr3N2 film has a higher trap density due to weaker bonding energy and a higher trap generation rate. In the experimental results for...