Word: gallium
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Dates: during 1970-1979
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...create what in effect is an electron freeway without these obstructing potholes, Bell Physicist Raymond Dingle and his colleagues built a semiconductor made of extremely thin, alternate layers of aluminum gallium arsenide (which they doped) and gallium arsenide (which they left pure). They reasoned that any electrons donated by the impurity would tend to migrate to the adjoining undoped gallium arsenide layer because of their tendency to seek what physicists call a lower energy state. Explains the Australian-born Dingle: "It's rather like the inclination of water to flow downhill." The new design worked. Isolated from the obstructing...
Varian Associates of Palo Alto has also come up with an idea to tap the sun as a source of power. The firm has developed a gallium arsenide solar converter only one-third of an inch in diameter that can produce 10 watts of electricity from the sunlight reflected from a concentrating mirror...
...negative charge)-an electrical current applied to this junction will flow in only one direction: from the N side to the P side, much the same as the oneway current flow in old-fashioned radio vacuum tubes called diodes. Even more significant, certain semiconductors, notably those made of gallium phosphide and gallium arsenide phosphide, will glow with a bright red light when current is flowing through them...
Bone to Blood. Current interest is focused on two isotopes of indium and gallium. At Ohio State University, Radiologists William W. Hunter Jr. and Xavier J. Riccobono worked with indium Ill, which was produced in the campus cyclotron. Using a special scanner, they found that the radioisotope concentrated heavily in bone in the first 24 hours after intravenous injection. As a result, X-ray photographs taken after the first day tended to reveal bone cancer. Even better, the radioactive molecules then joined proteins in the blood, concentrating in young, fast-growing tumors, thus revealing the sites of other cancers...
...front runner among today's diagnostic radioisotopes is gallium 67. Like indium, it can be virtually hand-crafted any time in any cyclotron. It, too, has a half-life of approximately three days-just right for selective concentration in a series of body tissues...