G6 mainframe computer depends on the use of silicon chips with copper connections that draw on solid-state physics research done in the firm's laboratory in the 1980s.

ECONOMIST: Philips

Telephone companies have used fiber for two decades, but the network boxes that reroute and switch the signals have always been based on silicon chips and copper circuitry.

FORBES: Hooked on Photonics

By contrast, check out today's announcement from Big Blue: Its new flagship eServer zSeries 990 runs up to 9 billion instructions per second on 32 processors--three times the system capacity of its predecessor z900--thanks in part to a palm-sized package of copper and silicon-on-insulator semiconductors with over 3.2 billion transistors and 500 meters of ultra-thin wire.

FORBES: IBM Does The On-Demand Dance

Nanosolar is one of several Silicon Valley startups that have attracted billions of dollars in venture capital to develop a thin-film technology called copper indium gallium selenide, or CIGS. Such solar cells use little expensive silicon, the main ingredient of conventional photovoltaic cells.

FORBES: Nanosolar Snares a Gigawatt in Orders for its Thin-Film Solar Panels

The three main types of thin film technologies use cadmium-telluride, copper-indium-gallium-selenide and amorphous-silicon to convert sunlight into electricity.

FORBES: First Solar Struggles Amid Decline Of Thin-Film Solar Market

At nearly 14%, the efficiency of the thin-film panels which are made from copper, indium, gallium and selenium (CIGS), is close to that of silicon, albeit being much cheaper to produce.

FORBES: 14% Efficiency for Thin-Film Solar Cells, but Where Will the Indium Come From?

Among the technologies are new ways of making already-commercialized formulations, like amorphous silicon and cadmium telluride, and newer formulations like CIGS, named for the elements it is made out of, copper, indium, gallium and selenium, and CIS, which leaves out the gallium.

FORBES: Chevron Stages Solar Talent Show