A5090121480- Thermal properties of materials
- Thermal Radiation and Cooling Technologies
- Thermography and Photoacoustic Techniques
- Advanced Thermodynamics and Statistical Mechanics
- Force Microscopy Techniques and Applications
- Acoustic Wave Phenomena Research
- Aerodynamics and Acoustics in Jet Flows
- Photoacoustic and Ultrasonic Imaging
- Metal and Thin Film Mechanics
- Ultrasonics and Acoustic Wave Propagation
- Laser-Matter Interactions and Applications
- Advanced Electron Microscopy Techniques and Applications
- Advanced Thermoelectric Materials and Devices
- Copper Interconnects and Reliability
- Nanofluid Flow and Heat Transfer
- Near-Field Optical Microscopy
- nanoparticles nucleation surface interactions
- Laser Material Processing Techniques
- Nanowire Synthesis and Applications
- Aerosol Filtration and Electrostatic Precipitation
- Photonic Crystals and Applications
- Advanced Physical and Chemical Molecular Interactions
- Spectroscopy and Laser Applications
- Quantum optics and atomic interactions
- Mechanical and Optical Resonators
Joint Institute for Laboratory Astrophysics
2011-2020
University of Colorado Boulder
2012-2019
Intel (United States)
2017
Ajinomoto (Japan)
2015
National Institute of Standards and Technology
2015
Calvin University
2010
Understanding thermal transport from nanoscale heat sources is important for a fundamental description of energy flow in materials, as well many technological applications including management nanoelectronics and optoelectronics, thermoelectric devices, nanoenhanced photovoltaics, nanoparticle-mediated therapies. Thermal at the fundamentally different that macroscale determined by distribution carrier mean free paths dispersion material, length scales sources, distance over which...
In this work, we generate and probe the shortest wavelength surface acoustic waves to date, at 45 nm, by diffracting coherent extreme ultraviolet beams from a suboptical phononic crystal. The short wavelengths correspond penetration depths of approximately 10 nm. We also measure dispersion in two-dimensional nanostructured crystals down for first time, showing that it is strongly influenced ultrashort depth, advanced finite-element analysis required model dispersion. Finally, use pulse...
Thermal transport at the nanoscale is much slower than plain diffusive in bulk, and has only lately become experimentally accessible. This limits informed design of nanosystems for $e.g.$ heat management nanoelectronics, or killing cancer cells using laser-heated nanoparticles. Using ultrafast pulses short-wavelength light, authors map continuous transition from isolated sources that cool slowly to closely spaced can quickly. improvement transfer simply by tuning geometry carries important...
Precise characterization of the mechanical properties ultrathin films is paramount importance for both a fundamental understanding nanoscale materials and continued scaling improvement nanotechnology. In this work, we use coherent extreme ultraviolet beams to characterize full elastic tensor isotropic down 11 nm in thickness. We simultaneously extract Young's modulus Poisson's ratio low-k a-SiC:H with varying degrees hardness average network connectivity single measurement. Contrary past...
We use short wavelength extreme ultraviolet light to independently measure the mechanical properties of disparate layers within a bilayer film for first time, with single-monolayer sensitivity. show that in Ni/Ta nanostructured systems, while their density ratio is not meaningfully changed from expected bulk, elastic are significantly modified, where nickel softens tantalum stiffens, relative bulk counterparts. In particular, presence or absence Ta capping layer influences Ni film. This...
Ultrathin films and multilayers, with controlled thickness down to single atomic layers, are critical for advanced technologies ranging from nanoelectronics spintronics quantum devices. However, thicknesses less than 10 nm, surfaces dopants contribute significantly the film properties, which can differ dramatically that of bulk materials. For amorphous being developed as low dielectric constant interfaces nanoelectronics, presence or soften degrade their mechanical performance. Here we use...
Photoacoustic nanometrology using coherent extreme ultraviolet (EUV) light detection is a unique and powerful tool for probing ultrathin films with wide range of mechanical properties thicknesses well under 100 nm. In this technique, short wavelength acoustic waves are generated through laser excitation nano-patterned metallic grating, then probed by diffracting EUV beams from the dynamic surface deformation. Both longitudinal within thin nanostructures can be observed as phase-sensitive...
Diatomic potentials for krypton are computed and also probed experimentally. For a probe-laser wavelength near $811$ nm, several strong dipole-dipole interactions produce purely-long-range potential wells in the singly excited manifold of ($s+p$) doubly ($p+p$) ($s+d$) potentials. Evidence resonant photoassociation into bound states these is observed emission ions ultraviolet photons from magneto-optically trapped cloud.
Photoacoustic spectroscopy is a powerful tool for characterizing thin films. In this paper we demonstrate new photoacoustic technique that allows us to precisely characterize the mechanical properties of ultrathin We focus an ultrafast laser onto nano-patterned film sample, launching both surface acoustic waves (SAWs) and longitudinal (LAWs). Coherent extreme ultraviolet pulses are then used probe propagation dynamics SAWs LAWs. The resulting signal on short (picosecond) long (nanosecond)...
Coherent extreme ultraviolet beams from tabletop high harmonic generation offer several revolutionary capabilities for observing nanoscale systems on their intrinsic length and time scales. By launching monitoring hypersonic acoustic waves in such systems, we characterize the mechanical properties of sub-10nm layers find that material densities remain close to bulk values while elastic are significantly modified. Moreover, within same measurement, by following heat dissipation dynamics...
We uncover a new regime of nanoscale thermal transport that dominates when the separation between heat sources is small compared with substrate's dominant phonon mean free paths. Surprisingly, interplay neighboring can facilitate efficient, diffusive-like dissipation.
We use coherent EUV beams to probe transport away from nanoheater arrays of varying width, spacing and substrate. validate new collectively-diffusive predictions, where nanowires cool faster when closely spaced than widely separated.
Coherent extreme ultraviolet beams from tabletop high harmonic generation offer revolutionary capabilities for observing nanoscale systems on their intrinsic length and time scales. By launching monitoring acoustic waves in such systems, we fully characterize sub-10nm films find that the Poisson's ratio of low-k dielectric materials does not stay constant as often assumed, but increases when bond coordination is bellow a critical value. Within same measurement, by following heat dissipation...
Using an ultrafast laser to excite 2D nanostructures, and coherent extreme ultraviolet light detect the resulting acoustic response, we observe characterize shortest-wavelength (35 nm) surface waves date.