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Editors' Column Surface Science Featured in NSF "Five-Year Outlook" The third in a series of National Science Foundation (NSF) reports on progress and prospects in U.S. scien tific research and technology features surface science among eight fields that are high on the list of national re search priorities. "The Five-Year Outlook on Science and Technology 1982" was prepared for the NSF by the Committee on Science, Engineering, and Public Poli cy (COSEPUP), a joint committee of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. As the product of a committee, one might ex pect "The Five-Year Outlook" to be pretty dry, but this publication con tains some excellent science writing, of a sort that might be found in an inter esting and up-to-date undergraduate textbook on contemporary topics in science. Surface science, according to the re port, deals with the first few layers of atoms at the surfaces of solids, the marked effects these atoms exert on the bulk solid, and their interactions with surrounding gases, liquids, and other solids. Recent progress in sur face science is attributed to the devel opment of pumps and related equip ment designed to achieve ultrahigh vacuum. Surface experiments must be performed under conditions of ultra high vacuum, in the range of 10~ 8 Pa, since clean surfaces are usually highly reactive. For example, a clean metal surface in a pressure of adsorbable gas of only 4 Χ 1 0 - 9 Pa will adsorb ap proximately 10% of a monolayer in one hour. Four analytical techniques were among the surface techniques de scribed briefly in the report. • Electron spectroscopy for chemical analysis (ESCA), also known as X-ray photoelectron spectroscopy (XPS), is used for elemental analysis and can provide information on the chemical state of atoms on the surface. • Auger electron spectroscopy (AES) is sensitive to the outermost few atom ic layers and can detect elements of both high and low atomic number (ex cept hydrogen). AES can also be com bined with slow removal of material
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by ion bombardment (sputtering) for profiling of chemical composition to near-atomic resolution through bulk material. • Secondary ion mass spectrometry (SIMS), in which ions ejected from a surface by primary ion bombardment are mass analyzed in a mass spectrom eter, can be used for trace element de tection and for analyses of insulator surfaces. • Ion-scattering spectroscopy (ISS) is a nondestructive technique used to study chemical composition in the outer monolayer of atoms on a surface. One of the most important offshoots of surface science technology is molec ular beam epitaxy, a technique that makes it possible to grow layered elec tronic and electrooptical devices with precise physical properties. According to the report, molecular beam epitaxy could not have been developed had not related surface science techniques been perfected earlier. In addition to the section on surface science, the report covers genetic engi neering, the molecular and genetic technology of plants, psychobiology, fluid turbulence, lasers, robots, and cell receptors for hormones and neuro transmitters. COSEPUP selected the topics, arranged for peer review of each chapter, and added a discussion on science policy issues. The report's conclusion on research priorities is that different fields of sci entific endeavor are inextricably tied in with each other: "Because of the strong effects that advances in knowl edge in one field may have on under standing phenomena in a quite differ ent field, and the major contributions to instrumentation, technique, and methodology that flow across disci plinary boundaries, it is essential that all of the major fields of science con tinue at strong levels of activity and excellence.... We cannot choose se lective excellence in science." "The Five-Year Outlook on Science and Technology 1982" (stock number 038-000-00530-8) is available for $5 from the Superintendent of Docu ments, Government Printing Office, Washington, D.C. 20402. Stuart A. Borman
