MRI: Acquisition of Cryogenic Capabilities for Microanalysis of Hard-Soft Nanoscale Materials in the Transmission Electron Microscope

University Of California - Merced, Merced CA

Investigators

Abstract

Acquisition of cryogenic capabilities for UC Merced's core electron microscopy facility will provide new research opportunities for nanoscale soft-hard materials and for all researchers in the physical and biological sciences, and engineering, at our fledgling campus. In addition, our partner campuses in the NSF Nanoscale Science and Engineering Center: Center Of Integrated Nanomechanical Systems will have access to this unique resource. It offers a combination of advanced microscopy techniques employed for hard materials, such as high-resolution transmission electron microscopy, electron energy-loss spectroscopy (EELS), and X-ray energy dispersive spectroscopy (XEDS), with the cryogenic specimen preparation and handling capabilities necessary for working with soft materials. It will also expand the scope of existing nanotechnology collaborative projects with industrial partners such as Hewlett-Packard. Specifically, the requested cryoultramicrotome will permit rapid freezing and sectioning of hard-soft specimens for TEM and SEM analysis without disruption of internal structures and interfaces that occur with common specimen preparation methods involving dehydration. The cryotransfer stage requested will allow transfer of these specimens into the TEM without warming and, in addition, allow them to be held at liquid nitrogen temperatures during analysis. This capability is critical for soft materials since it decreases specimen damage rates by a factor of 4-10X and prevents carbon migration to the electron beam position that makes microanalysis by thickness-sensitive techniques, such as EELS, otherwise nearly impossible. The combination of EELS, which is highly sensitive to light elements and does not require soft materials to be preferentially stained by heavy elements that introduce artifacts, with cryomicroscopy will enable nanoscale analysis of hard-soft materials in their native state. An XEDS detector has also been requested to complement our existing EELS capabilities. The requested instrumentation will enhance undergraduate teaching and research, in addition to outreach efforts. It will also assist in recruiting highly qualified faculty for our new undergraduate majors in bioengineering (introduced in 2005) and chemistry, materials chemistry, materials science and engineering, and physics (to be introduced in 2006). FTEs for these faculty hires have specifically been allocated in a manner to encourage interdisciplinary collaboration, with soft or soft-hard materials identified as a research focus for all but one of these majors. Combining very small-scale soft materials (polymers and biological materials) and hard materials (semiconductors, ceramics, and metals) leads to development of new technology for applications in human health, the environment; new energy; electronics; and aeronautics requires devices that. In order to understand how these devices work and to enable their development, an electron microscope and specimen preparation equipment are required that can study both the hard and soft components. We propose to combine very cold specimen preparation and holding techniques used for soft specimens with analysis techniques used for hard materials in order to achieve this. Our microscopy facility serves all researchers at our university in the physical sciences, engineering, and biology, and includes undergraduate research and teaching. For example, undergraduate students from our first freshman engineering class (entering in 2005) are already engaged in a microscopy research project that will require them to use these tools. Our students will incorporate their results into an exhibit that they are building for a local science museum serving area middle school students. The results will also be used for a technology education website that the students are developing. This website will in turn be used for interactive technology demonstrations by faculty visiting area middle and high schools.