Thin Gets Thick Coverage

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June 2, 1999: Huntsville, AL Efforts by people to get thin are nothing compared with the efforts made by the electronics industry. Thin-film technology is considered to be a key element of advanced electronics, from semiconductors to superconductors. The Space Vacuum Epitaxy Center, a NASA Commercial Space Center, is working with industry to help advance this important area of research and development. The center concentrates on four areas -- Nitride Materials and Devices, Advanced Oxide Materials and Devices, Photovoltaics and Nanostructures, and Optoelectronic Materials and Devices -- using both space - and ground-based research programs to make significant advances in technology. This work is profiled in a five page article in the March/April edition of the advanced semiconductor journal III-Vs Review.

The article notes the successes the Center has had in: developing advanced mid-range IR semiconductor lasers, which hold promise for both environmental monitoring and defense countermeasures; developing a unique multi-quantum well Indium Phosphide (InP) solar cells, that not only are radiation hardened, but thinner than conventional cells and with a greater end-of-life efficiency; advances in nitride coatings for high-temperature electronics, optoelectronic devices, and corrosion resistant coatings; and for using oxide thin films to fabricate high temperature superconducting (HTS) wires.

Semiconductor lasers are of intense commercial interest because of their small size, low power requirements, and low weight. Applied Optoelectronics Incorporated will help commercialize a mid infrared semiconductor laser that operates at room temperature. The Space Vacuum Epitaxy Center optimized the design and fabrication of the laser, which can be used for several applications including environmental monitoring on Earth and in space exploration. Because of its small size and weight, it is also ideal for use on aircraft as a part of defenses against heat-seeking missiles.

Improved solar cells are of interest, driven in part by the rapid explosion of communications systems that require satellites. The harsh environment of space, which includes exposure to radiation, can cut short the useful life of many types of solar cells. The new cells developed by the Space Vacuum Epitaxy Center offer improved performance along with a longer useful lifetime for satellite developers.

One opto-electronic device developed by the Center may have a biological optical application. A new and unique optical micro-detector has been developed that can be implanted into the eye to help restore sight in people with retinal damage. The detector "sees" in the visible light region, just like the eye, and has sufficient power to fire neurons in the optic nerve. Prototype detectors are in animal trials in collaboration with the University of Texas Health Science Center, and are expected to go to human trials under a cooperative industry venture, possibly helping as many as 2 million people a year.

High temperature superconductors offer a variety of fascinating possibilities for the future. One of the more immediate benefits may be in the form of energy savings, by reducing resistance in transmission lines and devices. The HTS wire developed by the Space Vacuum Epitaxy Center and the Texas Center for Superconductivity is being commercialized by Metal Oxide Technologies, Inc., and pilot plant production of HTS wire for power line transformers is expected in 2001.