What semiconductors famously did for computers and digital communication, they now promise to do for solar energy. Bring more efficiency, speed and lighter weight. European researchers are working on thin film solar cells using semiconductor materials. Some day those heavy glass covered roof panels will be like tube radios or the once-beloved CRT. Solar cells are now being made in Luxembourg using a semiconductor composed of copper, indium, gallium and selenium (CIGS). Scientists of the University of Luxembourg have also produced solar cells from an alloy which does not contain the costly indium, and made by a low cost galvanic process. So far silicon has been the element of choice for solar panels because it can be up to 25% efficient when converting solar energy into electricity. But it's heavy and it's expensive to manufacture the cells. Thin film tech promises to be much lighter and cheaper to produce if the efficiency levels can be driven high enough for it to replace current silicon based cells.