Hee-seon Bae

We report on the photodetecting properties of a ZnO-based thin-film transistor (TFT) that has been fabricated on a SiO2/p-Si substrate by rf magnetron sputtering at room temperature. Our ZnO-based TFT exhibited a saturation current level of about 6.5 μA under a gate bias of 40 V, decent electron mobility of 0.1 cm2/V s, and on/off current ratio of ∼106 in the dark. Illuminated by ultraviolet (λ=340 nm), blue (λ=450 nm), and green (λ=540 nm) light with intensity of 0.7 mW/cm2, our TFT displays hi

Polarization-sensitive photodetection has attracted considerable attention as an emerging technology for future optoelectronic applications such as three-dimensional (3D) imaging, quantum optics, and encryption. However, traditional photodetectors based on Si or III-V InGaAs semiconductors cannot directly detect polarized light without additional optical components. Herein, we demonstrate a self-powered linear-polarization-sensitive near-infrared (NIR) photodetector using a two-dimensional WSe<s

Luminescent silicon oxides containing radiative centers were obtained by using two different techniques. Silicon rich silicon oxides (SRSOs) were fabricated by rf magnetron sputter deposition and Ge-implanted SiO2 films were fabricated by ion implantation following the thermal oxidation of Si. Blue and violet photoluminescence were observed from the SRSO and the Ge-implanted SiO2, respectively. However, the electroluminescence (EL) spectra from both oxides exhibited red and near-infrared lumines

ZnO-based thin-film transistors (TFTs) have been fabricated by depositing ZnO (radio-frequency sputtering) on /p-Si substrates at various temperatures ranging from room temperature to 300°C. When rapid thermal annealing in a forming gas ambient was used for H treatment on ZnO, the TFTs prepared at 200°C exhibited a high field-effect mobility of but a low on/off current ratio of while those fabricated at room temperature showed a low mobility but a high on/off ratio The TFT fabricated at 300°C wa

Abstract 2D transition metal dichalcogenides (TMDs) have been extensively studied due to their excellent physical properties. Mixed dimensional devices including 2D materials have also been studied, motivated by the possibility of any synergy effect from unique structures. However, only few such studies have been conducted. Here, semiconducting 1D ZnO nanowires are used as thin gate material to support 2D TMD field effect transistors (FETs) and 2D stack‐based interface trap nonvolatile memory. F

We report on ZnO-based thin-film transistors (TFTs) fabricated using SiO2/p-Si substrates on which their ZnO channel layers have been deposited by rf sputtering at various temperatures: room temperature (RT), 100, and 200 °C. When they went through rapid thermal annealing in forming gas ambient (H2:N2=1:10) for n-type doping, the highest field effect mobility of ∼1.93 cm2/V s was achieved from ZnO-TFTs prepared using the deposition temperature of 200 °C while a low mobility (∼0.2 cm2/V s) was fr

Molybdenum disulfide (MoS₂) has been regarded as one of the most important n-type two-dimensional (2D) transition metal dichalcogenide semiconductors for nanoscale electron devices. Relatively high contact resistance (<i>R</i>_C) remains as an issue in the 2D-devices yet to be resolved. Reliable technique is very compelling to practically produce low <i>R</i>_C values in device electronics, although scientific approaches have been made to obtain a record-low <i>R</

Group IV monochalcogenides have recently shown great potential for their thermoelectric, ferroelectric, and other intriguing properties. The electrical properties of group IV monochalcogenides exhibit a strong dependence on the chalcogen type. For example, GeTe exhibits high doping concentration, whereas S/Se-based chalcogenides are semiconductors with sizable bandgaps. Here, we investigate the electrical and thermoelectric properties of γ-GeSe, a recently identified polymorph of GeSe. γ-GeSe ex

We report on the fabrication of an ultraviolet (UV)-detecting thin-film transistor (TFT) using NiOx as source∕drain electrodes and n-ZnO as its channel layer deposited on a SiO2∕p-Si substrate. Rapid thermal annealing of the TFT was carried out in an O2 ambient at 350°C for 1min to increase the transparency of NiOx. In an accumulation mode with a gate bias of 40V, a drain current of only 2μA was obtained in the dark. However, under an illumination of UV light with wavelength 325nm, the drain cur

Two-dimensional (2D)-layered material tantalum disulfide (2H-TaS 2 ) is known to be a van der Waals conductor at room temperature. Here, 2D-layered TaS 2 has been partially oxidized by utraviolet-ozone (UV-O 3 ) annealing to form a 12-nm-thin TaO X on conducting TaS 2, so that the TaO X /2H-TaS 2 structure might be self-assembled. Utilizing the TaO X /2H-TaS 2 structure as a platform, each device of a β-Ga 2 O 3 channel MOSFET and a TaO X memristor has been successfully fabricated. An insulator

Abstract Among advanced devices with 2D semiconductors, charge injection memory field effect transistors (CIM FETs) may be one of the most important and practical ones. Reported CIM FETs utilize three layers (for tunneling, trapping, and bulk dielectric) in general, resulting in high switching voltages over 10 V. Here, nonvolatile CIM FETs are fabricated with MoS 2 channel and hetero‐stack bilayer oxide dielectrics adopting 5 nm‐thin SiO 2 and 25 nm‐thick HfO 2 , where the charge traps are expec

Monoclinic semiconducting β-Ga 2 O 3 has drawn attention, particularly because its thin film could be achieved via mechanical exfoliation from bulk crystals, which is analogous to van der Waals materials’ behavior. For the transistor devices with exfoliated β-Ga 2 O 3, the channel direction becomes [010] for in-plane electron transport, which changes to vertical [100] near the source/drain (S/D) contact. Hence, anisotropic transport behavior is certainly worth to study but rarely reported. Here