A5100384074- Semiconductor materials and devices
- Ferroelectric and Negative Capacitance Devices
- MXene and MAX Phase Materials
- Electronic and Structural Properties of Oxides
- Ferroelectric and Piezoelectric Materials
- Advanced Memory and Neural Computing
- Graphene research and applications
- 2D Materials and Applications
- ZnO doping and properties
- Semiconductor materials and interfaces
- Advancements in Semiconductor Devices and Circuit Design
- Advancements in Battery Materials
- Catalytic Processes in Materials Science
- Metal and Thin Film Mechanics
- Nanowire Synthesis and Applications
- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- Perovskite Materials and Applications
- Copper Interconnects and Reliability
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced Sensor and Energy Harvesting Materials
- Concrete and Cement Materials Research
- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Quantum Dots Synthesis And Properties
The University of Texas at Dallas
2016-2025
Cornell University
2024-2025
Material Sciences (United States)
2020-2025
Korea Institute of Civil Engineering and Building Technology
2022-2024
Inha University
2022-2024
Yonsei University
2007-2024
Korea Institute of Science and Technology
2014-2024
Samsung (South Korea)
2002-2024
University of Illinois Urbana-Champaign
2023-2024
Chung-Ang University
2017-2024
Controllable doping of two-dimensional materials is highly desired for ideal device performance in both hetero- and p-n homojunctions. Herein, we propose an effective strategy MoS2 with nitrogen through a remote N2 plasma surface treatment. By monitoring the chemistry upon exposure using situ X-ray photoelectron spectroscopy, identified presence covalently bonded MoS2, where substitution chalcogen sulfur by determined as mechanism. Furthermore, electrical characterization demonstrates that...
The understanding of the metal and transition dichalcogenide (TMD) interface is critical for future electronic device technologies based on this new class two-dimensional semiconductors. Here, we investigate initial growth nanometer-thick Pd, Au, Ag films monolayer MoS2. Distinct morphologies are identified by atomic force microscopy: Pd forms a uniform contact, Au clusters into nanostructures, randomly distributed islands formation these different interfaces elucidated large-scale...
A template-directed synthesis strategy is an ideal tool to fabricate oxide nanotubes in that their physical dimensions can be precisely controlled and monodisperse samples harvested large quantity. The wall thickness of the controllable by varying deposition conditions, length diameter tailored accordance with templates used. wealth functional materials polymorphs deposited nanotubular structures various methods. This short review article describes recent progress made field template...
We report our investigation of the atomic layer deposition (ALD) HfO2 on MoS2 surface. In contrast to previous reports conformal growth flakes, we find that ALD bulk material is not uniform. No covalent bonding between and detected. highlight individual precursors do permanently adsorb clean surface but organic solvent residues can dramatically change nucleation behavior. then posit prior flakes had been exposed such organics solvents likely rely contamination-mediated nucleation. These...
We report on atomic layer deposited Hf0.5Zr0.5O2 (HZO)-based capacitors which exhibit excellent ferroelectric (FE) characteristics featuring a large switching polarization (45 μC/cm2) and low FE saturation voltage (∼1.5 V) as extracted from pulse write/read measurements. The in HZO is achieved by the formation of non-centrosymmetric orthorhombic phase, enabled TiN top electrode (TE) having thickness at least 90 nm. films are room temperature annealed 400 °C an inert environment for 1 min...
Graphene's single atomic layer of sp(2) carbon has recently garnered much attention for its potential use in electronic applications. Here, we report a memory application graphene, which call graphene flash (GFM). GFM the to exceed performance current technology by utilizing intrinsic properties such as high density states, work function, and low dimensionality. To this end, have grown large-area sheets chemical vapor deposition integrated them into floating gate structure. displays wide...
In this work, we demonstrate the growth of HfSe2 thin films using molecular beam epitaxy. The relaxed criteria have allowed us to layered, crystalline without misfit dislocations on other 2D substrates such as highly ordered pyrolytic graphite and MoS2. exhibit an atomically sharp interface with used, followed by flat, layers octahedral (1T) coordination. resulting is slightly n-type indirect band gap ∼1.1 eV a measured energy alignment significantly different from recent DFT calculations....
Single-crystalline silicon nanomembranes (Si NMs) represent a critically important class of material for high-performance forms electronics that are capable complete, controlled dissolution when immersed in water and/or biofluids, sometimes referred to as type "transient" electronics. The results reported here include the kinetics hydrolysis Si NMs biofluids and various aqueous solutions through range relevant pH values, ionic concentrations temperatures, dependence on dopant types...
The effect of room temperature ultraviolet-ozone (UV-O3) exposure MoS2 on the uniformity subsequent atomic layer deposition Al2O3 is investigated. It found that a UV-O3 pre-treatment removes adsorbed carbon contamination from surface and also functionalizes through formation weak sulfur-oxygen bond without any evidence molybdenum-sulfur disruption. This supported by first principles density functional theory calculations which show oxygen bonded to sulfur atom while simultaneously...
The difficulty in Schottky barrier height (SBH) control arising from Fermi-level pinning (FLP) at electrical contacts is a bottleneck designing high-performance nanoscale electronics and optoelectronics based on molybdenum disulfide (MoS2). For of multilayered MoS2, the Fermi level metal side strongly pinned near conduction-band edge which makes most MoS2-channel field-effect transistors (MoS2 FETs) exhibit n-type transfer characteristics regardless their source/drain (S/D) contact metals....
A systematic investigation established a significant correlation between the 2D to G band intensity ratio ( I / ) in Raman spectrum and internal kinetic barrier for sodium-ion transfer, achieving highest sodium plateau capacity of ∼400 mA h g −1 (A30 sample).
We present a facile route which combines the functionalization of highly oriented pyrolytic graphite surface with an atomic layer deposition (ALD) process to allow for conformal Al2O3 layers. While trimethylaluminum (TMA)∕H2O caused selective only along step edges, TMA∕O3 began provide nucleation sites on basal planes surface. O3 pretreatment, immediately followed by ALD chemistry, formed layers without any preferential at edges. This is attributed graphene ozone treatment, imparting...
We have investigated ozone adsorption on graphene using the ab initio density functional theory method. Ozone molecules adsorb basal plane with a binding energy of 0.25 eV, and physisorbed molecule can chemically react to form an epoxide group oxygen molecule. The activation barrier from physisorption chemisorption is 0.72 chemisorbed state has 0.33 eV. These energies indicate that gentle reversible. An atomic layer deposition experiment treated graphite confirmed presence uniform...
Exfoliated molybdenum disulfide (MoS2) is shown to chemically oxidize in a layered manner upon exposure remote O2 plasma. X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), and atomic force microscopy (AFM) are employed characterize the surface chemistry, structure, topography of oxidation process indicate that mainly occurs on topmost layer without altering chemical composition underlying layer. The formation S-O bonds short, plasma pins Fermi level conduction...
Understanding the structural stability of transition-metal dichalcogenides is necessary to avoid surface/interface degradation. In this work, 2H-MoTe2 with thermal treatments up 500 °C studied using scanning tunneling microscopy and transmission electron microscopy. On exfoliated sample surface at room temperature, atomic subsurface donors originating from excess Te atoms are observed presented as nanometer-sized, electronically-induced protrusions superimposed hexagonal lattice structure...
We report on the effect of Hf0.5Zr0.5O2 (HZO) film thickness ferroelectric and dielectric properties using pulse write/read measurements. HZO films thicknesses ranging from 5 to 20 nm were annealed at 400 °C for 1 min in a nitrogen ambient be compatible with back-end line thermal budget. As decreases, low-voltage operation (1.0 V or less) can achieved without dead layer effect, although switching polarization (Psw) tends decrease due smaller grain size. Meanwhile, 20-nm-thick prepared under...
The limited grain size (<200 nm) for transition metal dichalcogenides (TMDs) grown by molecular beam epitaxy (MBE) reported in the literature thus far is unsuitable high-performance device applications. In this work, fundamental nucleation and growth behavior of WSe2 investigated through a detailed experimental design combined with on-lattice, diffusion-based first principles kinetic modeling to enable large area TMD growth. A three-stage adsorption-diffusion-attachment mechanism identified...
Integration of graphene field-effect transistors (GFETs) requires the ability to grow or deposit high-quality, ultrathin dielectric insulators on modulate channel potential. Here, we study a novel and facile approach based atomic layer deposition through ozone functionalization high-κ dielectrics (such as Al(2)O(3)) without breaking vacuum. The underlying mechanisms have been studied theoretically using ab initio calculations experimentally in situ monitoring transport properties. It is...
Abstract Copper electrodes with a micromesh/nanomesh structure were fabricated on polyimide substrate using UV lithography and wet etching to produce flexible transparent conducting (TCEs). Well-defined mesh realized through the use of high-quality Cu thin films. The films radio-frequency (RF) sputtering single-crystal target—a simple but innovative approach that overcame low oxidation resistance ordinary Cu. Hybrid by adding capping layer either ZnO or Al-doped ZnO. sheet transmittance...
Layered two-dimensional (2D) materials have entered the spotlight as promising channel for future optoelectronic devices owing to their excellent electrical and properties. However, limited photodetection range caused by wide bandgap remains a principal challenge in 2D layered materials-based phototransistors. Here, we developed germanium (Ge)-gated MoS2 phototransistor that can detect light region from visible infrared (λ = 520-1550 nm) using detection mechanism based on band bending...
We present an Al2O3 dielectric layer on molybdenum disulfide (MoS2), deposited using atomic deposition (ALD) with ozone/trimethylaluminum (TMA) and water/TMA as precursors. The results of force microscopy low-energy ion scattering spectroscopy show that TMA ozone precursors leads to the formation uniform layers, in contrast incomplete coverage we observe when TMA/H2O Our Raman X-ray photoelectron measurements indicate minimal variations MoS2 structure after treatment at 200 °C, suggesting...