The Nebraska Nanoscale Facility (NNF) is a member of the NSF-funded National Nanotechnology Coordinated Infrastructure (NNCI) program which includes 16 major research centers in nanomaterials throughout the US. NNF, with support from the Nebraska Center for Materials and Nanoscience (NCMN) provides researchers from academia, government, and industry access to facilities with leading-edge instrumentation which enables innovations, discoveries, and contributions to education and commerce.
NNF offers a 10-week summer fellowship that provides undergraduate students with an opportunity for interdisciplinary research in a nanoscale science or engineering laboratory on the University of Nebraska-Lincoln campus. The Nebraska Nanoscale Facility summer research REU includes faculty mentors from the following university departments: Physics, Mechanical & Materials Engineering, Electrical and Computer Engineering, Civil Engineering and Chemical Engineering. The fellowships will carry a $4,500 stipend for ten weeks of research.
Competitive stipend: $4,500
Suite-style room and meal plan
Travel expenses to and from Lincoln
Campus parking and/or bus pass
Full access to the Campus Recreation Center and campus library system
To enable high-temperature operations, new materials will be required with high strengths in a variety of extreme environments. A promising class of novel materials known as oxide-dispersion-strengthened (ODS) alloys have the potential to perform in these environments. The industrial applications of these alloys, however, have been limited by existing joining technology, because traditional joining processes cause reactions at the micrometer scale in ODS alloys that lead to the deterioration of the joint's mechanical strength. The pulsed electric current joining process has emerged as a promising approach that can produce an outstanding ODS alloy joint with minimal changes at the micrometer scale. This project supports fundamental research to understand the relationships among the pulsed electric current joining process, the ODS alloy microstructure, and the resulting properties of the joints, giving insight into the mechanisms that enable high performance joints. This new knowledge will enable the translation of these high performance materials to applications in transportation, energy, and infrastructure.
Dr. Peter A. Dowben
Physics and Astronomy
Organic heterostructures can be made that have similar functionality to oxide and semiconductor devices
This project will focus magneto-electric organic or hybrid organic & inorganic heterostructures. The hybrid nanostructures will be characterized by electron spectroscopies and luminescence. The goals are classes of devices suitable as reactive luminescence chemical sensors, or devices that could exhibit unusual behavior is an electro-magnetic field.
This project involves the use of a “trochoidal electron monochromator” to reduce the energy width of an electron beam. Thermionically emitted electrons from a tungsten filament have energies that can differ by as much as 0.5 electron volts. In order to study electron-impact excitation of molecules, it is desirable to use incident beams of electrons that are much more narrow in energy space, with energies differing by no more than 0.05 eV. The goal of this project is to use a trochoidal monochromator, which separates electrons by energy using crossed electric and magnetic fields, to attain an even narrower width of 0.02 eV. The student on this project will gain experience with the production of high current, narrow energy-width electron beams, and will study various possible configurations of trochoidal monochromators using the sophisticated software package SIMION that can model the apparatus we have built.
Development of Ultra-Fast Spin-Polarized Electron Sources
We have recently demonstrated the use of a mode-locked laser oscillator to generate femtosecond pulses of spin-polarized electrons, based on the multi-photon ionization of GaAs tips . Polarized electrons have their spins pointing in a preferential direction. Among other applications, such electron pulses may prove useful in the study of microscopic magnetic dynamics on an ultrashort timescale.
The tips we have studied so far have electron-emitting structures that are microns in size. We hope to improve the emitted electron current and spin polarization by engineering nanometer-scale tips with liquid etching and ion-milling techniques. The student would learn the basics of femtosecond laser operation, Mott electron polarimetry, and the nano-machining of GaAs crystal structures.
 E. Brunkow, E. Jones, H. Batelaan, and T. J. Gay, “Femtosecond-laser-induced spin-polarized electron emission from a GaAs tip,” Appl. Phys. Lett. 114, 073502 (2019).
The field of nanomedicine offers the potential to improve the understanding and treatment of many disease processes by allowing researchers and clinicians the ability to deliver treatments to specific areas of the body, image where the treatments are going in real-time, and track responses. Therefore, the development of multifunctional nanoparticles has garnered significant attention especially for improving delivery into the brain for neurological diseases including traumatic brain injury, brain cancer, and dementia for which there is a significant lack of effective treatment options. These nanoparticles typically consist of a small core that acts as a scaffold to carry imaging agents for tracking nanoparticle localization in the body through various imaging modalities such as magnetic resonance and fluorescence imaging, therapeutic moieties for treatment, and targeting agents for binding cell surface receptors expressed in target tissue. However, the translation of nanomedicine into clinical use has been hindered by complicated nanoparticle designs that make reproducible synthesis and scale-up difficult. Therefore, a goal of the Kievit lab is to develop simplified synthesis strategies for multifunctional nanoparticles to improve their translatability.
The student working with Dr. Kievit will be introduced to nanoparticle drug delivery vehicles as well as various mechanisms to gain entry into the brain. Simultaneously, the student will be trained on various nanoparticle synthesis and characterization strategies for different types of nanoparticles including magnetic and polymeric nanoparticles that can be imaged using both MRI and fluorescence imaging. Once this is complete, the student should be able to formulate a hypothesis on how to achieve the project goal as well as methods to test this hypothesis. Advanced students will also learn how to image the nanoparticles using our 9.4T MRI and fluorescence microscopes. During the middle of the summer, the student will use their developed skills to test their hypothesis by generating and interpreting characterization and imaging results. During the final third of the summer the student will reformulate their hypothesis based on their preliminary results and use their methods to re-test this hypothesis (search and re-search!). During this project, the student is expected to gain an understanding of the limitations of neurological disease treatment and how nanoparticle engineering strategies can be used to overcome these limitations. The student will get hands-on experience in nanoparticle synthesis strategies, characterization methods, and use of different imaging systems. The student will also get the experience of processing, analyzing, and interpreting experimental data, as well as data presentation in written and oral form.
Nanoscale magnetic imaging of low-dimensional materials using diamond quantum sensors
Understanding the behaviour of spins, charges, and phonons in quantum materials is at the heart of condensed matter physics. In the past few decades, a wide range of new materials showing exciting new physical phenomena has been discovered and explored. Current characterization techniques do not provide the combined spatial resolution and sensitivity required to map their properties at the nanoscale (< 10 nm). Recently, a new technique has emerged for measuring physical properties (magnetic, optical, electrical…) at the nanometer scale based on optical detection of the electron spin magnetic resonance of nitrogen vacancy (NV) centers in diamond, Fig. 1a. Negatively charged NV centers, constituted of a substitutional nitrogen adjacent to a vacancy site, are bright, perfectly photostable emitters (650-800 nm) that exhibit high-contrast optical detected magnetic resonance (ODMR).
The NV spin-triplet ground state features a zero-field splitting D = 2.87 GHz between states m s = 0 and m s = ± 1, Fig. 1b. Intersystem crossing to metastable singlet states takes place preferentially for NV centers in the m s = ± 1 states, allowing optical readout of the spin state via spin-dependent fluorescence [ ref ]. The application of an external magnetic field breaks the degeneracy of the m s = ± 1 state and leads to a pair of transitions whose frequencies depend on the magnetic field component along the N-V symmetry axis. In this project we use NV-diamond based microscopes for mapping magnetic phenomena of materials at the nanoscale.
One of the magnetic systems we are interested to explore are magnetic skyrmions. Skyrmions are nanoscale chiral spin textures proposed for the next generation of ultradense magnetic memories for spintronics applications. They can occur as two-dimensional ground states in magnetic systems with strong spin orbit coupling and broken inversion symmetry. Of particular interest are room-temperature (RT) skyrmions, recently observed in stacks composed of ultrathin ferromagnetic layers sandwiched between heavy metal layers. The effect of interfaces, strength of spin-orbit interaction on stabilizing the skyrmions is not well understood. Imaging their full spin structure is challenging owing to the need for sensitive nonperturbative magnetic probes with spatial resolution below 10 nm. In this project we employ a recently built scanning diamond probe microscope ( Fig. 1c ) to map RT skyrmions in magnetic layers, composed of ultrathin Co layers sandwiched between 5d transition metal layers such Ir, Pt, and W.
Flexible and precise micromachining of ultrathin glasses by dual-wavelength, pulse tunable, high-power femtosecond laser
Ultrathin glasses have great supplication for electronics, displays, and sensing devices. There has been an increased interest from both industry and academia to develop techniques for micromachining ultrathin glasses (< 500 µm) with high quality and efficiency. Glass is a brittle material; however ultrathin glasses have a greater flexibility to them. Because of these properties any micro cracks or edge property changes post processing can cause the samples to break more easily. We believe femtosecond laser machining can solve the issue of cutting and drilling ultrathin glasses in a fast and cost efficient manner without the potential post process damages. Femtosecond (fs) lasers are in the category of ultra-short pulse lasers. The pulse length of an fs laser causes the energy to be transferred to the material in a shorter time than the thermal conversation of photons. This causes electron detachment and coulomb explosion to remove material without the thermal affects that can be caused by other methods (scoring, breaking, long pulse laser breaking).
This project will focus on the design and fabrication of soft actuators based on microgels. The efforts will focus on developing effective geometries for desired movements and chemical processes for onboard power generation.
The sensing and monitoring of metal additive manufacturing processes
The objective of this project is to instrument sensors in metal 3D printers at University of Nebraska-Lincoln and obtain sensor data so that faults can be predicted in the part during the printing process. Students will work with graduate students to instrument a metal 3D printer with a sensor array, program the sensors in labview, and acquire data from the sensors using experiments. Another aspect of this project is examining the printed parts for flaws, such as pores, using X-Ray scanners.
Characterization of the passive film formed on the embedded steel in cementitious materials
Hydrated cementitious materials are highly alkaline and have a pH of greater than 12.5. As a result, when reinforcing steel is embedded in the cementitious materials such as concrete, a layer of passive film is formed on the surface of the steel, which protects it from corrosion. Preliminary SEM images show that cement hydration products are not deposited on the surface of the embedded steel uniformly. Therefore, this project hypothesizes that the thickness of passive film varies spatially. As an undergraduate researcher, you will be responsible for preparing test samples, determining the morphology of various steel specimen using transmission electron microscopy (TEM), performing qualitative and quantitative analysis on the results, and reporting to the faculty mentor every week.
Complex oxides exhibit various properties, such as ferromagnetism, ferroelectricity, superconductivity, magnetoresistance, etc. These properties owe to their complex crystal structure and electronic structures. Despite decades of research on complex oxides, which include at least two metal elements, the majority of these materials haven’t been thoroughly investigated, due to large number of metal elements, various compositions, and a plethora of crystal structures.
In this project, the undergraduate student will learn and carry out synthesis of novel complex oxide using solid state reaction and characterize their structural and magnetic properties using x-ray diffraction and magnetometry. The objective is to establish structural phase diagram of transition metal complex oxides. The current focus is on their ferroelectric and magnetic properties. [see J. Appl. Phys. 125, 244101 (2019); doi: 10.1063/1.5098488]
Figure 1. Structural phase diagram of Sc-substituted rare earth ferrites. The two dimensions are Sc/rare earth ratio x and the rare earth species R.