News

Stanford has been selected as one of the eight Centers for Cancer Nanotechnology Excellence by the National Cancer Institute. Professor Wang is the co-Principal Investigator spearheading this effort and is co-lead of Project 1 (magneto-nano protein chips and sorters). Professors Sinclair, Dai, Nishi, and Kelly also lead projects or core resources for the Center. For more information, click here.

Professor McGehee gets GCEP funding to study organic photovoltaic cells and nanotubes in solar cells

Professor McGehee is co-PI with Professor Zhenan Bao (Chemical Engineering) and UCLA Professor Yang Yang (MSE) for a new program, "Advanced Materials and Devices for Low-Cost and High-Performance Organic Photovoltaic Cells." Further, he is also co-leading a new one-year exploratory research effort, "Nanotube Networks as Transparent Electrodes for Solar Cells," with Professor David Goldhaer-Gordon (Physics). Further information on these projects may be

Professor Clemens gets DOE funding to study hydrogen storage

Professor Clemens, along with a team of researchers from many other universities and institutions, has been awarded a grant from the Department of Energy to establish a Center of Excellence for hydrogen storage research. For more on this project, click here.

Sebastian Osterfeld wins several awards

Sebastian Osterfeld, a doctoral student in the Wang Group, has recently received a competitive ARCS Scholarship for his work on microfluidic magnetic biosensors. This honor adds to Sebastian's previous accolades, including a Whittaker Fellowship and a Stanford Graduate Fellowship.

Aditi Chandra wins an Intel PhD Fellowship

Aditi Chandra has been selected as a recipient of a 2004-05 Intel Foundation PhD Fellowship Award at Stanford University.

Eric Guyer wins several awards

Eric Guyer has been selected as a recipient of a 2004-05 Intel Foundation PhD Fellowship Award at Stanford University. Eric also recently recieved the 2004 Daniel Cubicciotti Award from the San Francisco Bay Area Section of the Electrochemical Society and an Outstanding Poster Award at the Materials Research Society spring meeting.

Peter Hess wins a graduate ASM/SAMPE Joint Scholarship

Peter Hess has been awarded a graduate ASM/SAMPE Joint Scholarships for 2004. The scholarship recipients were selected by a committee composed of representatives from both ASMI and SAMPE chapters. TThe ASMI/SAMPE Joint Student Scholarship award was created to encourage undergraduate and graduate students to further their career in Materials Science or Engineering.

Hyoungsub Kim wins MRS Graduate Student Award

Hyoungsub Kim, a PhD student jointly advised by Prof. Paul McIntyre (MSE) and Prof. Krishna Saraswat (EE), received a Materials Research Society (MRS) Graduate Student Award at the Spring MRS Meeting in San Francisco on April 12-16, 2004. Earlier this year, he was presented with the Simon Karecki Award of the Semiconductor Research Corporation, which recognizes graduate students who have made outstanding contributions to science and engineering problems that have significant environmental implications for the semiconductor industry.

Hyoungsub, who recently completed the requirements for his PhD degree in Materials Science and Engineering at Stanford, is an expert in atomic layer deposition (ALD) of metal oxide thin films. His thesis research focused on basic materials studies of ALD-grown high permittivity metal oxide dielectrics and their integration in field effect transistor devices. Some of the most exciting applications for ALD-grown dielectrics which Hyoungsub has investigated include their use in novel non-planar field effect devices, including semiconducting nanotube and nanowire transistors. Hyoungsub plans to remain at Stanford as a postdoctoral research associate affiliated with the Stanford Initiative in Nanoscale Materials and Processing, a new industry-supported research effort aimed at developing molecular-scale understanding of electronic materials processing.

Paul McIntyre is promoted to Associate Professor

In December of 2003, Paul McIntyre was promoted to the position of Associate Professor. Please join us all in congratulating him for this accomplishment.

Daniel Aubertine wins the MRS Graduate Student Gold Medal Award

In December of 2003, Daniel Aubertine competed against other graduate students at the Materials Research Society Meeting in Boston and won the Gold Medal Award. The title of his talk was "An x-ray diffraction study of concentration and strain dependent interdiffusion in Si/SiGe multilayers." Daniel is the fourth student in Paul McIntyre's group to win a medal at an MRS meeting. He recently graduated and will go to work for Intel.

As SiGe films are introduced into deeply scaled, ultra-fast MOS devices, it is increasingly clear that interdiffusion at Si/SiGe interfaces is a significant problem. Strained Si MOSFET's, for example, typically utilize a thin, epitaxial, strained Si channel grown onto a relaxed SiGe layer. For these structures, out-diffusion of Ge from the SiGe layer into the Si channel is a factor limiting the practical thermal exposure during processing. Predicting the degree of intermixing is difficult because, in principle, the interdiffusion process is influenced by the local Ge concentration and film strain. Development of a robust model for Si/SiGe interdiffusion requires that these effects be isolated and quantified.

Aubertine's work is aimed at quantifying the couplings between interdiffusion and strain relaxation using x-ray diffraction from Si/SiGe superlattices. Although less commonly applied to semiconductor diffusion than techniques that map out concentration profiles directly, x-ray diffraction from compositionally modulated structures has a long history as an ultra-high-sensitivity probe of both interdiffusion and strain relaxation. The elegance of this approach is that it allows these two dynamic processes to be probed simultaneously with a single measurement technique. \

Establishing an empirical model to describe the interaction of Ge concentration and film stress with interdiffusion has an immediate technological application to predicting the effects of thermal processing on SiGe devices. It is also important from a fundamentally scientific point of view, as it will provide useful test cases for atomic scale modeling of diffusion phenomenon in Si and SiGe alloys.

Bill Nix Elected to the National Academy of Sciences

On April 29, Bill Nix was one of 72 new members elected to the National Academy of Sciences (NAS) for distinguished and continuing achievements in original research. Established by a congressional act in 1863, NAS is a private organization of scientists and engineers whose active members are dedicated to the furtherance of science and its use for the general welfare. Upon request, the academy advises the federal government on matters of science and technology. Election to NAS is one of the highest honors that can be accorded a U.S. scientist or engineer.

Bill Nix is the Lee Otterson Professor in the School of Engineering. His research interests include the mechanical properties of bulk materials, thin films, and nanostructures, and the atomic-scale imperfections that control these properties. Current projects focus on the development of experimental techniques for the study of stresses and mechanical properties of thin films and nanowires and on the modeling of these properties. He is also engaged in research on the mechanical properties of bulk metallic glasses.

Nix received a bachelor's degree in metallurgical engineering from Jose State College in 1959, a master's degree in metallurgical engineering from Stanford in 1960 and a doctorate in materials science from Stanford in 1963. He is also a member of the National Academy of Engineering and a fellow of the American Academy of Arts and Sciences.

Wendy Wright receives the Walter J. Gores Teaching Award

Wendelin (Wendy) J. Wright, a finishing Ph.D. student in the MSE department, has been selected to receive a Walter J. Gores Teaching Award from Stanford. She will be recognized for her outstanding work as a teaching assistant at Stanford's 112th commencement exercises on June 15, 2003. As the University's highest award for teaching, the Gores Award celebrates achievement in educational activities that include lecturing, tutoring, advising, and discussion leading. Wendy will be cited for the enthusiasm, initiative and dedication that she brings to teaching and for her extraordinary talents as a teacher. The citation also recognizes her gifts as a mentor of undergraduates and her intellectual passion and joy for teaching. Wendy joins Prof. John Bravman as the only members of the MSE department to have received a Gores Award.

Congratulations Wendy!

The Geballe Laboratory for Advanced Materials Has Acquired a New SEM and Focused Ion Beam

The Geballe Laboratory for Advanced Materials has recently acquired a new scanning electron microscope (SEM) and a new focused ion beam instrument (FIB) as part of the developing Nanocharacterization Facility. These tools are state-of-the-art instrumentation from FEI Company, providing the Stanford materials community with exciting new research capabilities: a Sirion SEM with high resolution and low voltage capabilities, and a Strata Dual Beam 235 with both electron and ion beam columns for combined FIB/SEM work. Both have Schottky field-emission electron sources and are equipped with energy dispersive spectrometry (EDS) for compositional analysis. The Sirion SEM has a resolution of 1.5 nm at 10kV and 2.5 nm at 1 kV. The Strata Dual Beam FIB offers new opportunities for device cross-section characterization and nanoscale fabrication using the localized etching and depostion capabilities of the ion beam, supplemented by several gas injection systems (GIS). The FIB is also equipped with an Omniprobe manipulator for in situ transfer. These instruments are located in McCullough Building and operate as service centers. For more information see the GLAM website.

Ultra-Thin Metal Oxide Dielectrics for Nanometer-Scale Transistors

Work by members of Prof. Paul McIntyre's group has demonstrated the passivation of germanium and semiconducting single-walled carbon nanotube (SWNT) surfaces with deposited high dielectric constant (high-k) films. These ultra-thin dielectric layers are necessary for fabrication of field-effect transistors on Ge substrates and SWNT structures, semiconducting materials that may replace silicon in future transistor devices.

The high-k/Ge transistor research team includes MSE doctoral students David Chi, Hyoungsub Kim and Kang-Ill Seo, who are all members of McIntyre's research group in the Geballe Laboratory for Advanced Materials, and EE doctoral student Chi-On Chui of Prof. Krishna Saraswat's research group. In addition to supervision by McIntyre and Saraswat, MSE Consulting Prof. Baylor Triplett has helped guide research by the team members.

Growth of high-k metal oxide dielectric layers on hydrophobic Ge (100) has been performed using a novel processing method pioneered in McIntyre's lab: UV-ozone oxidation of vapor-deposited metal precursor films. The oxides investigated so far, ZrO2 and HfO2, have dielectric constants in the range 20 - 30, and are thermodynamically stable with respect to reduction by the Ge substrate. In fact, these oxides are sufficiently stable compared to GeO2, that they appear to prevent formation of a low-k germanium oxide interface layer between the deposited dielectric and the Ge (100) surface. This is a key requirement for use of the dielectric in nanometer-scale transistors.

Fully-functioning Ge pMOS transistors containing a ZrO2-based gate dielectric layer and Pt gate electrode have been fabricated and show very promising electrical characteristics. The maximum temperature used in the entire fabrication sequence was 400 degrees C. Because of the large low-field mobility of the Ge single crystal substrate, these high-k/Ge transistors have twice the carrier mobility of state-of-the-art Si devices. Results of this work will be described in December 2002 at the International Electron Devices Meeting in San Francisco.

Hyoungsub Kim and Prof. McIntyre have also been involved in an active collaboration on processing high-k/SWNT transistors involving Prof. Hongjie Dai of Chemistry and his doctoral student Ali Javey. This research has focused on studying the properties of nanotube devices in which the SWNT semiconductor channel is passivated by a 5 - 8 nm thick layer of ZrO2 deposited using the atomic layer deposition (ALD) system in the McIntyre lab. ALD-grown ZrO2 was found to produce only a modest change in the conduction properties of the nanotubes while permitting operation of SWNT devices at gate biases exceeding 3 V. The uniformity, high-k and very small thickness of the ALD-ZrO2 layer resulted in outstanding electrical characteristics for the SWNT transistors, the best obtained to date for carbon nanotube devices. Results of this collaborative research will be reported in an upcoming article in Nature Materials.

The Global Climate and Energy Project

On November 20, President John Hennessy announced the Global Climate and Energy Project (G-CEP), a multi-million-dollar research collaboration among scientists, engineers and major corporations to develop technologies that foster a global energy system to reduce greenhouse emissions. Several members of the Materials Science and Engineering Department expect to be involved in this exciting project, which is described in the Global Climate and Energy Project website.

BioMagnetic Sensing Project Launched

A multidisciplinary team consisting of Profs. Shan Wang and Bob White from MSE, Dr. Chris Webb and Prof. Ron Davis (Biochemistry and Stanford Genome Technology Center), Prof. Z. X. Shen (Applied Physics), Dr. Shouheng Sun from IBM Research, and Profs. Luke Lee and Paul Alivisatos from UC Berkeley have just been awarded a major research grant by US Defense Advanced Research Projects Agency (DARPA) to work on "An Integrated High-Sensitivity DNA Detection and Display System Based on Magnetic Nanoparticles for Use in Biological Warfare and Functional Genomics". One of the major goals in this project is to develop a sensitive and quantitative non-optical detection system for DNA microarrays (or gene chips). This will ultimately allow single-molecule detection of DNA. Additionally, magnetic detection may eliminate the costly and time-consuming polymerase chain reaction (PCR) step currently required for target amplification.

Magnetic nanoparticles (sphere) are being developed to tag unknown DNA fragments (single strand). The latter hybridize with known oligonucleotide probes and become immobilized on a magnetic sensor. The detection of magnetic nanoparticles then allows us to identify and quantify the unknown DNA fragments that are complimentary to the probes.

Stanford Engineering Launches Strategic Initiative in Materials by Beth Curran

Capitalizing on Stanford's strengths in the areas of nanomaterials, nanoscience, and nanotechnology, the Stanford Materials Council recently recommended the launch of an Advanced Materials Initiative. This initiative proposes a broad expansion of current materials research goals, with a fundamental component being the creation of centralized instrumentation facilities and infrastructure.

Materials research and teaching at Stanford are currently carried out by over 90 faculty members from ten departments and three schools. While the Materials Science and Engineering (MSE) Department is arguably the "home" of materials research and teaching at Stanford, materials research is distributed across many departments, largely because it is applications-driven and many applications reside in departments other than MSE. Intellectual challenges for materials research in the next decade are largely, but not exclusively, dominated by the science and technology of nanoscale systems.

One of the critical factors that will enhance materials research is a set of core research experimental facilities for fabrication, synthesis, and characterization of new materials. Over the next several years, the plan is to establish, equip, and staff several key laboratories for the broad materials community at Stanford. This will result in the following benefits: 1) provide enabling facilities for materials faculty, 2) substantially improve national visibility for the materials program at Stanford, 3) enhance opportunities for students to do experimental work at the forefront of materials research, and 4) offer an integrated materials curriculum cutting across departments, designed to make it easy for students to take a variety of materials classes.

The five proposed laboratories (described below) would be shared both internally by faculty and students from a variety of departments and schools as well as by outside academic and industry users. One of these laboratories, the Stanford Nanofabrication Facility (SNF), actually already exists on campus but would be improved with new equipment and additional resources. The four other labs recommended are: a Nano-Characterization Facility, an X-ray Laboratory for Advanced Materials, a Soft and Hybrid Materials Research Facility, and a Computational Materials Science Laboratory.

"The result of this major initiative is that Stanford will have the most advanced materials research capabilities in the world, with faculty and students to match them," explained Professor Arthur Bienenstock, chair of the Materials Council. "These capabilities will, in turn, lead to entirely new research endeavors while strengthening Stanford's ties to the very fine academic, governmental and industrial institutions that surround us. The entire San Francisco Bay region will be enriched and even more innovation will be stimulated."

Nanofabrication Facility SNF provides micro- & nano-fabrication resources to a broad community of researchers. In addition to traditional electronics, research projects include nanotechnology, biotechnology, MEMS, and integrated optics. SNF already functions as a shared facility and can be a model for other laboratories. Sharing the use of a laboratory significantly reduces the financial burden on any one research team and is a cost-effective resource for the university as well as outside academic and industry partners.

Nano-Characterization Facility It is well known that many opportunities for development of new, advanced materials involve the nanometer size level. At the same time, more traditional technologies such as integrated circuits and information storage are also moving to similar dimensions. Understanding the underlying mechanisms associated with these innovations requires material characterization at the same scale. The Nano-Characterization Facility will house two complementary sets of instrumentation that are prominent in materials characterization: microscopic inspection and surface chemical analysis.

X-ray Laboratory for Advanced Materials The creation of a Stanford X-Ray Laboratory for Advanced Materials is envisioned to be an integral part of Stanford's drive to become the world's forefront research institution on advanced materials. The university has a unique opportunity to utilize the nearby Stanford Synchrotron Radiation Laboratory (SSRL) to house such a laboratory. The laboratory would serve three important functions: priority access for Stanford faculty and students to SSRL's x-ray beam lines with technical support staff to ensure their effective use, office and laboratory space for faculty and students, and training and conference facilities.

Soft and Hybrid Materials Research Facility This facility would include the full range of characterization and processing instrumentation suitable for study of small organic molecules as well as macromolecules of both synthetic (polymer) and biological (protein, DNA) origin. In addition, facilities for the synthesis of organic and hybrid organic/inorganic/biological materials need to be created. New faculty members with interests in tissue engineering are expected to benefit significantly from this facility.

Computational Materials Science Laboratory The fundamental challenge in computational materials science is to keep pace with the rapidly increasing computing power and to maintain simulation software along with changing hardware platforms. Without a continuous investment in hardware and software maintenance, the computing power of current state-of-the-art computing facilities will be reduced to only 10% of state-of-the-art within five years. This unique situation makes any computing facility have a very short useful lifetime, and the Computational Materials Science Laboratory at Stanford would be planned to continuously upgrade its state-of-the-art computing facility.

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