After Café

WHEN: Select Tuesdays 11:00 AM - 11:45 AM, 

WHERE: 3rd Floor Commons, Millennium Science Complex

WHO: Any student, staff, or faculty interested in learning more about MCL capabilities

A casual opportunity immediately following the Millennium Café to learn about the breadth of analytical capabilities within the Materials Characterization Laboratory (MCL).  These brief (30 minute) multi-technique and interdisciplinary talks will highlight applications (not theory) to provide useful insights to novice and experienced researchers working across various science and engineering challenges.

Watch Past After Café Talks on YouTube

After Café Fall 2024 Series

After Café: More than Just a Picture: Integrating CT into Research

Computed tomography (CT) is a non-destructive technique that is used to investigate the 3D structure in a wide range of materials of both biologic and synthetic origin, from manufactured metal parts to delicate insect specimens. With this technique, samples can be analyzed ranging from the size of cockroach antenna to a bear skull. Using image analysis software, visualization, processing, and quantification of internal and external features can produce eye-catching images, videos, and both quantitative and qualitative information, all with little to no harm to the sample. I will discuss different ways to utilize CT images in your research. 

Michelle Quigley, Assistant Research Professor, Institute of Energy and the Environment, Energy and Environmental Sustainability Laboratories, Center for Quantitative Imaging 

After Café: Rigor Matters: Accurate Analyses at Elevated Temperatures

Many areas of research characterize samples under standard conditions and attempt to extrapolate these results to temperatures or an atmosphere far from ambient.  Numerous non-ambient capabilities are available within MCL, these require careful planning and special hardware, but the data collected under non-ambient conditions can be invaluable.  Variable temperature accessories are perhaps the most convenient and commonly used for non-ambient analysis.  However, there are no accessories where the controller setpoint accurately reflects the sample temperature at the location being analyzed.  This talk will highlight two methods (FTIR and XRD) where the MCL has developed accurate and precise temperature calibration protocol. 

Jordan Meyet
After Café: Thermal Analysis Capabilities, Trade Offs, and Limitations

While thermal property analyses (TGA, DSC, SDT) are often considered routine techniques the published literature demonstrates that these are frequently misused or underutilized.  I will review the capabilities of the MCL thermal analysis suite to include highlighting the less obvious information that can be obtained with each technique.  Additionally, the tradeoffs associated with each technique will be discussed to provide practical guidance for choosing the proper analyses.  Finally, I will discuss what characterization should be performed prior to thermal analyses and introduce the “health check” tests which MCL routinely performs to ensure our instrumentation is operating properly. 

Dean Anderson
After Café: Evaluating Residual Stress and Strain States Using X-ray Diffraction Techniques

X-ray diffraction (XRD) techniques provide an attractive, nondestructive method to determine residual stresses by measuring atomic plane spacings in diffracting volumes and relating them to strain using the sin^2(psi) technique. This presentation will review the theory behind these calculations, identifying characteristics to look for during data analysis, a review of the advantages and limitations surrounding different experimental geometries, such as Bragg-Brentano and Grazing Incidence X-ray Diffraction (GIXRD), and an overview of MCL X-ray capabilities.  I will conclude with a short discussion about identifying when synchrotron x-ray capabilities may be appropriate for your specific experimental conditions. 

Taylor S. Wood – PhD Candidate, Materials Science and Engineering 

After Café: New Ways to Characterize Biological Samples using Scanning Transmission Electron Microscopy and Liquid Atomic Force Microscopy

Biological samples are often difficult to image due to their thickness, low contrast, and native hydrated state. We will discuss two different techniques available for analyzing these types of samples in Penn State's Material Characterization Lab, including scanning transmission electron microscopy (STEM) with energy dispersive spectroscopy (EDS), and liquid atomic force microscopy (AFM). Using a TEM with STEM-EDS capabilities, we can quickly acquire elemental maps at resolutions of less than 1 nm and sensitivities of less than one atomic percent. This provides many opportunities to answer important scientific questions related to the presence of metal atoms or other biologically relevant elements such as S, P, Ca, etc. in cells and biological structures in general. The other benefit of STEM imaging is the ability to image thicker samples with enhanced mass-thickness contrast as compared to TEM. This also makes the technique ideal for thick biological samples and removes some of the need for heavy metal staining in fixed samples. STEM imaging under cryo conditions or in liquids is also possible but poses significant challenges at high resolutions. However, we can use an AFM in liquid mode to capture the surface topography of biological samples with sub-nanometer-scale resolution in their native hydrated state. Since biological samples typically contain ~80 % water, removing water from or freezing a material can significantly alter its chemistry and structure and affect any analysis performed on that material. The capability of liquid AFM includes high-resolution imaging in fluid/hydrated samples, nanomechanical mapping, nanoindentation, high-speed AFM to molecular movements, and functionalized tip for molecular interaction. 

Jennifer Gray, Sarah Kiemle
After Café: Irreproducible or Low-Quality Data? How’s Your Prep?

Quality materials characterization always begins with proper sample preparation.  All too often individuals rush to analyze a sample without considering how its intrinsic state will influence results.  Considering sample roughness, thickness, critical feature size, or potential sources of contamination are just a few questions to ponder before jumping on that fancy analytical instrument.  The MCL has revamped its sample preparation laboratory with new expertise, equipment, and procedures.  I will highlight how to get started using this lab and provide general tips & tricks to improve the rigor and reproducibility of your work.

Bob Hengstebeck
After Café: Infrared Emission Characterization: Practical Approaches and Applications

Measuring the thermally emitted radiation of coatings, devices, and other materials has become an increasingly important topic as coatings are being applied to manage increasing heat loads on our infrastructure and as devices are pushed to higher limits. Characterizing the emissive property is relevant for developing technologies in energy conversion, imaging, and thermal management.  The MCL has recently developed methods to quantify the wavelength and intensity of the thermally emitted radiation from various samples ranging in size from 10’s of microns to the macro-scale. 

Tawanda Zimudzi, Linxiao Zhu

After the Café Spring 2024 Series

After Café: Spectroscopic Methods for Electronic Property Characterization at the MCL

MCL now offers a range of analytical techniques that can be used to determine important electronic properties of your device or material system. These properties include: band gap (Eg), work function (WF), valence band maximum (VBM), ionization energy (IE), electron affinity (EA), conduction band minimum (CBM) and carrier concentration. We have techniques for studying electronic defect states in the band gap which can impact device performance and for those making heterojunctions we can determine valence and conduction band offsets. This talk will provide an overview of these parameters and how they can be measured within MCL along with details about sample requirements and limitations.

Jeff Shallenberger
After Café: How Rough is my Surface? It Depends.

The specific technique, details of the acquisition method, along with how data is processed all influence the quantification of surface roughness.  Furthermore, the commonly reported roughness parameters of average roughness and RMS roughness are often inadequate to fully characterize the texture of a surface.  This talk will provide an overview of what differences you should expect between surface roughness data coming from AFM, OP, and even stylus profilometry as well as an introduction to advanced surface texture parameters.

Tim Tighe
After Café: Mapping Elemental Composition and Chemical Bonding at the Nanoscale

EDS in SEM is often used to map compositional information across length scales ranging from microns down to many nanometers and EDS in TEM can provide analogous information on the nanometer scale. However, it is often helpful to have information complementary to the elemental information attainable via EDS. The MCL has several techniques capable of providing information about chemical bonding, oxidation states, and chemical structure. In this talk, we will highlight several spectroscopic techniques such as XPS, EELS, Raman, or FTIR which can provide information at various length scales and across a range of materials.

Jennifer Gray
After Café: Methods for Determining Crystallite and Single Crystal Orientation

For many materials the direction (or orientation) of the crystal planes impacts the overall properties.  The simplest example is the difference between a single-crystalline and polycrystalline sample.  But even polycrystalline samples need not be completely random; some crystalline planes may preferentially align with certain directions.  Such a sample is said to be oriented or textured. Orientation influences grain boundaries, mechanical and electrical properties, and more.  We will discuss X-ray scattering, electron microscopy and other methods available in the MCL that can be used to determine orientation of crystalline domains across a range of materials.

Anthony Richardella
After Café: Strategies for Better Cross-Sectional Imaging

Cross-sectional SEM imaging is commonly used in nanofabrication for coating thickness measurement, process verification, and failure analysis. Cleaving is frequently the method of choice for generating a cross-sectional sample for analysis.  However, this approach may inadvertently damage the sample which then poses challenges for accurate imaging.  By using a focused ion beam (FIB) instrument it is possible to create highly site specific cross sections with minimal artifacts for almost any structure/device/material.  In this talk I will highlight several applications for the efficient use of FIB ross-sectional imaging to accurately characterize a range of devices and layered material systems.

Bangzhi Liu
After Café: Authorship on Publications: Who, When, Why, How, and Other Considerations

A publication is often considered to be a key product of academic research. It is the public-facing record of the research that is archived and available for others to read, as well as part of a portfolio that impacts the professional advancement of researchers. Authorship is therefore an important aspect of a publication. This talk will highlight some considerations that are relevant when determining the list of authors that is included on a publication. Emphasis will be placed on practical guidelines and best practices that are recommended by federal funding agencies, journals, and institutions. 

Raymond Schaak
After Café: Molecular Spectroscopy Imaging on the Micro-and Nano-scale

While most researchers are familiar with standard “macro” FTIR, Raman, and UV-Vis.  It is less known that the MCL currently maintains instrumentation capable of acquiring high spatial resolution data for all of the aforementioned molecular spectroscopy techniques.  This talk will discuss the applications of AFM-IR (Nano-IR), Micro-FT-IR and Micro-UV-Vis while highlighting the limitations of each techniques as it relates to sample preparation requirements and common artifacts.

Maxwell Wetherington, Tawanda Zimudzi