A5040927032- Laser Material Processing Techniques
- Laser-induced spectroscopy and plasma
- Thin-Film Transistor Technologies
- Nanowire Synthesis and Applications
- Nanomaterials and Printing Technologies
- Laser-Ablation Synthesis of Nanoparticles
- Nonlinear Optical Materials Studies
- Nanofabrication and Lithography Techniques
- Near-Field Optical Microscopy
- nanoparticles nucleation surface interactions
- 2D Materials and Applications
- ZnO doping and properties
- Silicon Nanostructures and Photoluminescence
- Carbon Nanotubes in Composites
- Ocular and Laser Science Research
- Nanopore and Nanochannel Transport Studies
- Advanced Materials and Mechanics
- Quantum Dots Synthesis And Properties
- Force Microscopy Techniques and Applications
- Advanced Sensor and Energy Harvesting Materials
- Silicon and Solar Cell Technologies
- Advanced Surface Polishing Techniques
- Surface Roughness and Optical Measurements
- Electrohydrodynamics and Fluid Dynamics
- Integrated Circuits and Semiconductor Failure Analysis
University of California, Berkeley
2016-2025
University of California System
2004-2025
Lawrence Berkeley National Laboratory
2007-2025
Berkeley College
2009-2023
Sandia National Laboratories
2022
Samsung (South Korea)
2020
Lam Research (United States)
2019
Stamatopoulos and Associates (Greece)
2019
Lawrence Livermore National Laboratory
2006-2016
Stony Brook University
2016
We report gas and water flow measurements through microfabricated membranes in which aligned carbon nanotubes with diameters of less than 2 nanometers serve as pores. The measured exceeds predictions the Knudsen diffusion model by more an order magnitude. values calculated from continuum hydrodynamics models three orders magnitude is comparable to rates extrapolated molecular dynamics simulations. permeabilities these nanotube-based are several higher those commercial polycarbonate...
In this paper, in order to increase the power conversion efficiency we demonstrated selective growth of "nanoforest" composed high density, long branched "treelike" multigeneration hierarchical ZnO nanowire photoanodes. The overall light-conversion DSSCs was almost 5 times higher than constructed by upstanding nanowires. is due greatly enhanced surface area for dye loading and light harvesting, also reduced charge recombination providing direct conduction pathways along crystalline...
All-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that laser sintering of inkjet-printed metal nanoparticles enables low-temperature deposition as well high-resolution patterning overcome resolution limitation current inkjet direct writing processes. To process combined with implementation air-stable carboxylate-functionalized polythiophenes, organic transistors were fabricated ambient pressure and...
Biological pores regulate the cellular traffic of a large variety solutes, often with high selectivity and fast flow rates. These share several common structural features: inner surface pore is frequently lined hydrophobic residues, filter regions contain charged functional groups. Hydrophobic, narrow-diameter carbon nanotubes can provide simplified model membrane channels by reproducing these critical features in simpler more robust platform. Previous studies demonstrated that nanotube...
The sky is a natural heat sink that has been extensively used for passive radiative cooling of households. A lot focus on maximizing the power roof coating in hot daytime using static, cooling-optimized material properties. However, resultant overcooling cold night or winter times exacerbates heating cost, especially climates where dominates energy consumption. We approached thermal regulation from an all-season perspective by developing mechanically flexible adapts its emittance to...
One-step direct nanoimprinting of metal nanoparticles was investigated to fabricate nano-/microscale metallic structures such as nanodot and nanowire arrays. This done at low temperatures pressures, utilizing the melting temperature viscosity nanoparticle solutions. Through precise control fluidic properties solution mold design, high-quality nanoscale features with no or negligible residual layer were nanoimprinted. Nanoscale electronic devices also demonstrated, including resistors...
We report a highly flexible planar micro-supercapacitor with interdigitated finger electrodes of vertically aligned carbon nanotubes (VACNTs). The electrode structures are patterned on thin polycarbonate substrate facile, maskless laser-assisted dry transfer method. Sputtered Ni is used to reduce the in-plane resistance VACNT electrodes. An ionogel, an ionic liquid in semi-solid matrix, as electrolyte form fully solid-state device. measure specific capacitance 430 μF cm−2 for scan rate 0.1 V...
Tissue morphogenesis and organ formation are the consequences of biochemical biophysical cues that lead to cellular spatial patterning in development. To model such events vitro, we use PEG-patterned substrates geometrically confine human pluripotent stem cell colonies spatially present mechanical stress. Modulation WNT/β-catenin pathway promotes via geometric confinement condensation process during epithelial-mesenchymal transition, forcing cells at perimeter express an OCT4+ annulus, which...
The critical size limit of voltage-switchable electric dipoles has extensive implications for energy-efficient electronics, underlying the importance ferroelectric order stabilized at reduced dimensionality. We report on thickness-dependent antiferroelectric-to-ferroelectric phase transition in zirconium dioxide (ZrO2) thin films silicon. emergent ferroelectricity and hysteretic polarization switching ultrathin ZrO2, conventionally a paraelectric material, notably persists down to film...
As an analogy of the magic-angle twisted bilayer graphene, a coupled-mode theory is formulated for low-angle honeycomb photonic crystals, discovering flat bands with non-Anderson-type localization.
Gigahertz (GHz) femtosecond (fs) lasers have opened possibilities for enhancing and controlling the laser machining quality to engineer physicochemical properties of materials. However, fundamental understanding laser-material interactions by GHz fs has remained unsolved due complexity associated ablation dynamics. Here, we study dynamics copper (Cu) bursts using in situ multimodal diagnostics, time-resolved scattering imaging, emission spectroscopy. A combination probing techniques reveals...
Abstract Recent advancements in manufacturing, finite element analysis (FEA), and optimization techniques have expanded the design possibilities for metamaterials, including isotropic auxetic structures, known applications like energy absorption due to their unique deformation mechanism consistent behavior under varying loads. However, achieving simultaneous control of multiple properties, such as optimal characteristics, remains challenging. This paper introduces a systematic approach that...
The laser-based curing of printed nanoparticle ink to create microlines (resistors) electrical resistivity approaching that bulk gold was investigated. present work relies on laser absorption in both the and sintered layer, as well transport thermal energy substrate resulting solvent vaporization deposition sintering. morphology properties line can be controlled by modulating spatial distribution beam intensity. Based understanding underlying physics, a process circumvents serious drawback...
A high resolution organic field effect transistor (OFET) fabrication process has been developed based on the selective laser sintering of ink-jet printed nanoparticle inks and recent development an air stable carboxylate-functionalized polythiophene semiconducting polymer. The entire device characterization are performed at room temperature, ambient pressure, environment without using complex lithographic methods. This low temperature OFET great potential for realizing inexpensive, large...
A digital, direct nanoscale metal patterning method is developed using femtosecond laser digital processing of nanoparticles for electronics fabrication without conventional vacuum deposition or a photolithography mask. This expected to be potential alternative the electron beam lithography arbitrary in single-step, low-temperature, and non-vacuum environments.
Pulsed laser irradiation of nanosecond duration is used in a variety applications, including deposition thin films and micromachining. Of fundamental interest the prediction evaporative material removal rates, as well velocity, density, temperature distributions ejected particles functions laser-beam pulse energy, temporal distribution, irradiance density on target surface. In order to address these issues, present work establishes new computational approach for thorough treatment heat...
Nanoscale patterning and electronics fabrication on flexible polymer substrates via direct nanoimprinting of metal nanoparticles was demonstrated. The nanoparticle solution enables a simple one-step with very low pressure temperature. Electrical structural characterizations substrate during cyclic bending deformations verify the robustness nanoimprinted structures to mechanical deformation conditions.