Surface & Interface Science

Surface and interface science stands as a fascinating realm of scientific exploration, delving into the intricate interactions that occur at the boundaries of materials.

Spectroscopy and microscopy techniques serve as indispensable tools, enabling researchers to unravel the intricacies of molecular structures and surface dynamics with unprecedented precision.

X-RAY PHOTOELECTRON SPECTROSCOPY (XPS) SYSTEM

The Estrada Group maintains a PHI VersaProbe II Scanning XPS Microprobe with 128 channel detector. Scanning x-ray microprobe technology, that provides high performance XPS large area spectroscopy, superior micro-area spectroscopy, chemical imaging, and secondary electron imaging with a raster scanned 10 µm diameter x-ray beam. The information XPS provides about chemical compositions is of great value in basic research as well as in many industrial applications including: nanostructures, thin films, polymer surface modification, catalysis, corrosion, adhesion, semiconductor, dielectric materials and magnetic media.

ATOMIC FORCE MICROSCOPY

The Estrada Group led the purchase of a Bruker nanoIR3 atomic force microscope awarded through grant from the Murdock Charitable Trust. The tool is now managed by the Surface Science Laboratory. The Bruker nanoIR3 provides nanoscale chemical, thermal, and optical properties mapping of materials. The Bruker nano-IR3 is situated on a 12” thick concrete slab that is isolated from the main building and designed to meet or exceed Vibration Criterion D (VC-D, 250 µ-inches/second or ~6.35 µm/s), the typical standard for AFM installations. Tight, 24/7 temperature control within the laboratory ensures <2°F/hr drift (i.e., ±1°C), with Class 100,000 HEPA filtration to remove particulates and low laminar airflow (<20 fpm) to minimize air currents and HVAC noise/vibrations.

An anteroom enables donning of booties and use of tacky mats to prevent introduction of dust into the lab. Overhead racks for housing power supplies and other associated peripherals (e.g., lock-in amplifier) are situated directly above the area allocated for the 4’ x 8’ floating optical table to combine ease of access with minimization of thermal gradients at table level. All utilities necessary for the AFM-IR system are provided via overhead carriers, including multiple 15 A/120 V duplex electrical outlets, fast Ethernet connections, dry compressed air, and ultra-high purity nitrogen for floating the optical table and purging the system of water vapor. The Bruker nanoIR3 has AFM-IR, s-SNOM, and SThM capabilities.

CONFOCAL RAMAN SPECTROSCOPY

Confocal Raman spectroscopy, a powerful analytical technique, takes center stage in the exploration of molecular composition and structural details within materials. The Estrada Group manages the Horiba LabRam HR Evolution Confocal Raman Microscope. The tool is equipped with 442 nm, 532 nm, and 633 nm excitation wavelengths. Environmental stages are available for temperature dependent Raman and Photoluminescence from 80K to 1300K.

OPTICAL MICROSCOPY

Optical microscopy serves as a cornerstone in the visual exploration of materials, offering a window into the intricate details of structures at the microscopic level. The Estrada Group maintains a Zeiss Axio Imager M2m Materials Microscope with Fluorescence, Differential Interference Contrast (DIC), Phase Contrast, and Polarization capabilities.

SURFACE ENERGY AND WETABILITY

Surface energy and wettability play pivotal roles in determining the interactions between materials and their surroundings. The Estrada Group employs a Biolin Scientific T200-Auto3 Attension Theta Optical Tensiometer to unravel the intricacies of surface properties.

Access this facility

Interested may contact Prof. David Estrada to learn about collaboration and/or requesting characterization services. A full list of equipment is here:

Bruker nanoIR3S AFM
- Nanoscale IR Spectroscopy
  - s-SNOM providing near field amplitude and phase images and spectra
  - Resonance Enhanced AFM-IR mode
  - Tapping AFM-IR spectroscopy & chemical imaging mode
  - Point Spectroscopy & IR chemical mapping capability
  - HotSPOT enabled selection of any point or series of points within the AFM image to obtain localized nanoIR spectra
  - IR imaging at a fixed wavenumber of interest; ratio spectral images at user defined wavenumbers
  - Export AFM-IR spectra to optional external IR databases for identification of unknown materials
  - Analysis Studio software package for acquisition, control, analysis &export
- Atomic Force Microscopy
  - X,Y scanner with range of 50μm by 50μm using closed loop linearization for precise positioning performance
  - Standard AFM modes supported: Tapping, Phase Imaging, Contact, Lateral Force, Force Curves, Force Modulation, EFM/MFM mode
  - Integrated bright-field optical microscope with a 10X objective for viewing the sample and probe with a resolution of 1.5 microns
  - Computer controlled XY sample positioning stage, 8.0 mm travel in X, 8.0mm travel in Y
  - Analysis Studio software package for acquisition, control, and analysis
- Mid-IR Laser Source for s-SNOM and AFM-IR Broadband Spectroscopy
  - Femtosecond based laser source with a spectral range of approx. 2.5μm to
  - 14μm wavelength (700 – 4,000cm-1)
  - For use with s-SNOM & AFM-IR technique. Configuration includes:
  - Includes additional nanoIR laser integration module & associated optics for broadband spectroscopy operation for complete operation
  - Provides s-SNOM spectroscopy across a spectral range of 700 to 4,000cm^-1
  - Provides s-SNOM imaging in the range of <700->2,000cm^-1
  - Provides AFM-IR spectroscopy and imaging in the range of 700-2,000cm^-1
- AM-nIR-TA Thermal Analysis
  - Transition Temperature Microscopy (TTM)
- Relative thermal conductivity/temperature mapping (SThm)
Horiba Scientific LabRAM HR Evolution Raman Microscope
- 442 nm, 532 nm, and 633 nm (visible) excitation wavelengths available
  - 325 nm (UV) excitation wavelength possible with additional laser line filter
- 10x, 20x, 50x, and 100x bright field objectives
  - LWD 20x objective also compatible with DIC, fluorescence, and polarized light
- 600 and 1800 line/mm holographic diffraction gratings blazed for 500-600 nm
- 8 m monochromator equipped with confocal pinhole
- Thermoelectrically cooled Si CCD array (256 x 1024) detector
- ~1 µm lateral resolution at 633 nm (~500 nm maximum resolution with UV excitation)
- 80 x 100 mm motorized stage for point by point Raman mapping
- µm step size with ± 1 µm repeatability and accuracy
- DuoScan optics for high speed, high resolution mapping
- Multipass attachment for acquisition of solution Raman spectra in a standard optical cuvette
- Environmental stages for temperature dependent Raman and Photoluminescence from 80K to 1300K
PHI VersaProbe II Scanning XPS Microprobe
- Scanned, micro-focused, monochromatic x-ray beam
- X-ray beam induced secondary electron imaging
- Dual beam charge neutralization
- Large area XPS
- Micro-area XPS
- Chemical state imaging with 128 data channels
- Sputter depth profiling
- Floating column argon ion gun
- Compucentric Zalar rotation
- Angle dependent XPS
- Five axis automated sample manipulator
- 25 mm and 60 mm diameter sample holders
Zeiss Axio Imager M2m Materials Microscope
- Transmitted Light
- Reflected Light
- DIC imaging
- Phase contrast imaging
- Polarization imaging
- Automated X-Y-Z mechanical stage
- Colibri fluorescence imaging
- Axiocam 105 Color Camera
- 10X thru 100X objectives
- ZenCore Analysis Software
Biolin Scientfic T200-Auto3 Attension Theta Optical Tensiometer with Automatic XYZ stage and Pipette Dispenser
- Sessile Drop Contact Angle Measurements
- Dynamic Contact Angle
- Surface Free Energy Calculations
- Surface and Interfacial Tension Measurements
- Topography Attachment for Surface Roughness Analysis
Biolin Scientfic Attension Theta Lite Tensiometer
- Sessile Drop Contact Angle Measurements
- Dynamic Contact Angle
- Surface Free Energy Calculations
- Surface and Interfacial Tension Measurements
QEA PIAS-II Image Analysis System with Field Verification Target.