Hyungjun Kim

Semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDCs) are promising gas-sensing materials due to their large surface-to-volume ratio. However, their poor gas-sensing performance resulting from the low response, incomplete recovery, and insufficient selectivity hinders the realization of high-performance 2D TMDC gas sensors. Here, we demonstrate the improvement of gas-sensing performance of large-area tungsten disulfide (WS 2 ) nanosheets through surface functionalization u

The synthesis of atomically thin transition-metal disulfides (MS2) with layer controllability and large-area uniformity is an essential requirement for their application in electronic and optical devices. In this work, we describe a process for the synthesis of WS2 nanosheets through the sulfurization of an atomic layer deposition (ALD) WO3 film with systematic layer controllability and wafer-level uniformity. The X-ray photoemission spectroscopy, Raman, and photoluminescence measurements exhibi

Abstract 2D transition metal dichalcogenides (TMDs) have attracted much attention for their gas sensing applications due to their superior responsivity at typical room temperature. However, low power consumption and reliable selectivity are the two main requirements for gas sensors to be applicable in future electronic devices. Herein, a p‐type (WSe 2 /WS 2 ) and n‐type (MoS 2 /WSe 2 ) photovoltaic self‐powered gas sensor is demonstrated using 2D TMD heterostructures for the first time. The gas

The effective synthesis of two-dimensional transition metal dichalcogenides alloy is essential for successful application in electronic and optical devices based on a tunable band gap. Here we show a synthesis process for Mo1-xWxS2 alloy using sulfurization of super-cycle atomic layer deposition Mo1-xWxOy. Various spectroscopic and microscopic results indicate that the synthesized Mo1-xWxS2 alloys have complete mixing of Mo and W atoms and tunable band gap by systematically controlled compositio

The efficient synthesis of two-dimensional molybdenum disulfide (2D MoS2) at low temperatures is essential for use in flexible devices. In this study, 2D MoS2 was grown directly at a low temperature of 200 °C on both hard (SiO2) and soft substrates (polyimide (PI)) using chemical vapor deposition (CVD) with Mo(CO)6 and H2S. We investigated the effect of the growth temperature and Mo concentration on the layered growth by Raman spectroscopy and microscopy. 2D MoS2 was grown by using low Mo concen

Two-dimensional (2D) transition-metal dichalcogenides have attracted significant attention as gas-sensing materials owing to their superior responsivity at room temperature and their possible application as flexible electronic devices. Especially, reliable responsivity and selectivity for various environmentally harmful gases are the main requirements for the future chemiresistive-type gas sensor applications. In this study, we demonstrate improved sensitivity of a 2D MoS₂-based gas s

Semiconducting two-dimensional transition-metal dichalcogenides are considered promising gas-sensing materials because of their large surface-to-volume ratio, excellent electrical conductivity, and susceptible surfaces. However, enhancement of the recovery performance has not yet been intensively explored. In this study, a large-area uniform WSe₂ is synthesized for use in a high-performance semiconductor gas sensor. At room temperature, the WSe₂ gas sensor shows a significa

Rare earth oxide (REO) atomic layer deposition (ALD) processes are investigated for hydrophobic coatings. Thermal and plasma-enhanced ALD (PE-ALD) Er 2 O 3 and Dy 2 O 3 are developed using the newly synthesized Er and Dy precursors bis-methylcyclopentadienyl-diisopropyl-acetamidinate-erbium and bis-isopropylcyclopentadienyl-diisopropyl-acetamidinate-dysprosium, with H 2 O and O 2 plasma counter oxidants. The Er and Dy precursors show typical ALD growth characteristics with no nucleation incubati

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have attracted considerable attention as promising building blocks for a new generation of gas-sensing devices because of their excellent electrical properties, superior response, flexibility, and low-power consumption. Owing to their large surface-to-volume ratio, various 2D TMDCs, such as MoS₂, MoSe₂, WS₂, and WSe₂, have exhibited excellent gas-sensing characteristics. However, exploration

With devices being scaled down to the nanometer regime, the need for atomic thickness control with high conformality is increasing. Atomic layer deposition (ALD) is a key technology enabler of nanoscale memory and logic devices owing to its excellent conformality and thickness controllability. Plasma-enhanced ALD (PE-ALD) allows deposition at significantly lower temperatures with better film properties than in conventional thermal ALD. These benefits make PE-ALD more attractive for nanoscale dev