This article is based on the 2004 Von Hippel Award address by Nick Holonyak Jr. (University of Illinois at Urbana-Champaign). Holonyak received the award for “his many contributions to research and development in the field of semiconductors, not least for the first development of semiconductor lasers in the useful visible portion of the optical spectrum.” The talk was presented on Holonyak's behalf by Russell Dupuis on December 1, 2004, at the Materials Research Society Fall Meeting in Boston.

With the discovery of the transistor by Bardeen and Brattain in 1947, and as a consequence of carrier injection and collection, the hole indeed became equal to the electron. The semiconductor took on new importance, as did the study of electron–hole recombination, first in the transistor materials Ge and Si, and then in III–V crystals (e.g., GaAs and GaP). Beyond Si and its indirect-gap and heterojunction limitations, the directgap III–V materials, particularly III–V alloys, made possible lasers and light-emitting diodes (LEDs)—and thus optoelectronics.

The direct-gap III–V alloy LED after four decades of development exceeds in performance the incandescent lamp (as well as other forms of lamps) in much of the visible range. Beyond growing display applications, it has put conventional lighting under longrange threat with a semiconductor lamp—an “ultimate lamp” that promises unusual performance and energy savings. In principle, the LED or laser, basically a p–n junction, is an ultimate lamp that cannot be exceeded.

Simple diagrams are used to show the transformation of a thin sample of intrinsic, direct-gap semiconductor from an ideal “flat-band” photopumped recombination-radiation light source into a current-driven, p–n junction “ultimate lamp,” a light-emitting diode.

The following article is based on the plenary presentation given by Mildred S. Dresselhaus of the Massachusetts Institute of Technology on November 29, 2004, at the Materials Research Society Fall Meeting in Boston. Advanced materials offer new promise for addressing some of the grand societal challenges of our future, including that of global energy. This article will review opportunities that have opened up at the nanoscale, with materials of reduced dimensionality and enhanced surface-to-volume ratio. Some examples of research accomplishments and opportunities at the nanoscale will be described, with special attention given to the potential for advanced materials and nanoscience to have an impact on the grand challenges related to a sustainable energy supply for the 21st century and beyond.

The following article is an edited transcript based on the David Turnbull Lecture given by Frank S. Bates of the University of Minnesota on December 1, 2004, at the Materials Research Society Fall Meeting in Boston. Bates received the award for “pioneering contributions to the fundamental understanding of structure and properties of complex polymeric materials, particularly block copolymers and polymeric vesicles, coupled with outstanding lecturing, writing, teaching, and educational leadership.” This article outlines the research accomplishments of a group of Bates' students that provide fresh insights into the molecular factors governing complex self-assembly in block copolymers. Three triply periodic and multicontinuous network phases were discovered in poly(isoprene-bstyrene-b-ethylene oxide) (ISO) triblock copolymers.Two cubic phases (Q230 and Q214) and an orthorhombic phase (O70) were identified using small-angle x-ray scattering (SAXS), transmission electron microscopy (TEM), birefringence measurements, and dynamic mechanical spectroscopy, along with level-set modeling. These findings establish a concrete strategy for locating potentially valuable network morphologies in ABC triblock copolymer melts.

This article is an edited transcript based on the MRS Medal Award presentation given by Jacob N. Israelachvili on December 1, 2004, at the Materials Research Society Fall Meeting in Boston. An expanded article on this topic will be published in the August 2005 issue of the Journal of Materials Research. Recent experimental results have shown how surface texture, surface energy, and the bulk properties of materials can affect their adhesion and friction and, in turn, determine some of the fundamental differences between modes of failure of materials. Theoretical modeling and computer simulations, among other methods, provide examples and comparisons of surfaces that are rough or smooth, hard or soft (for example, viscoelastic), adhesive or non-adhesive, and dry (unlubricated) or lubricated. Such studies clarify the molecular and atomic basis of many well-established adhesion and tribological laws and empirical observations, revealing insights and relationships between nanoscale (molecular) and macroscale processes. Also of critical importance are the effects that occur at the sub-nanoscale, that is, in the sub-angstrom or picoscale regime. It is demonstrated and argued that the ultrafine picoscale details of a surface lattice, or its roughness, can be the most important factor in determining its friction (and mode II fracture), whereas such effects are quantitatively less important for adhesion and mode I fracture processes.

This article is an edited transcript based on a presentation given by Rebecca M. Bergman (Medtronic Inc.) as part of Symposium X—Frontiers of Materials Research on November 30, 2004, at the Materials Research Society Fall Meeting in Boston. Materials innovations have been at the heart of many important advances in implantable medical devices. Miniaturization, improved durability and longevity, enhanced biocompatibility, and controlled delivery are several areas where materials innovations have been important in advancing medical products and therapies. The demands on materials used in the physiological environment are stringent and include requirements related to materials properties as well as safety, quality, and reliability. Looking ahead, materials will undoubtedly continue to be an enabling technology for future innovations in medicine, including novel therapies such as tissue engineering, cell therapy, and gene therapy.

The following article is based on a presentation given by Samuel I. Stupp of Northwestern University as part of Symposium X—Frontiers of Materials Research on April 13, 2004, at the Materials Research Society Spring Meeting in San Francisco. Materials designed at the molecular and supramolecular scales to interact with cells, biomolecules, and pharmaceuticals will have a profound impact on technologies targeting the regeneration of body parts. Materials science is a great partner to stem cell biology, genomics, and proteomics in crafting the scaffolds that will effectively regenerate tissues lost to trauma, disease, or genetic defects. The repair of humans should be minimally invasive, and thus the best scaffolds would be liquids programmed to create materials inside our bodies. In this regard, self-assembling materials will play a key role in future technologies. This article illustrates how molecules are designed to assemble into cell scaffolds for human repair and provides examples relevant to brain damage, fractures of the skeleton, spinal cord injuries leading to paralysis, and diabetes.