HIGH TEMPERATURE SURVIVABLE CONTACTS FOR GALLIUM ARSENIDE SPACE SOLAR CELLS

EXISTING METALLIC-TYPE CONTACTS ON GALLIUM ARSENIDE (GAAS) HAVE NOT BEEN STABLE AT HIGH TEMPERATURES BECAUSE OF INTERDIFFUSION AND/OR ALLOYING OF THE GAAS TOP LAYER. HIGH TEMPERATURE CONTACTS TO GAAS SPACE PHOTOLTAIC CELLS ARE BEING DEVELOPED BASED ON THE FORMATION OF A HIGHLY-STABLE INTERMEDIATE DEGENERATE SEMICONDUCTOR LAYER BETWEEN THE GAAS AND A HIGH TEMPERATURE METAL ALLOY. THE INTERMEDIATE SEMICONDUCTOR APPROACH LEADS TO THE BEST HIGH TEMPERATURE PERFORMANCE BECAUSE IT USES A METAL WHICH IS A SEMICONDUCTOR RATHER THAN ALLOYING WITH THE GAAS. UNDER THIS APPROACH, BOTH THE INTERMEDIATE SEMICONDUCTOR LAYER AND THE CONTACT METAL ARE EXPECTED TO REMAIN STABLE AT TEMPERATURES IN EXCESS OF 600 DEGREES C. THIS CONTACT WILL MAKE POSSIBLE NEW, HIGHER CONCENTRATION SOLAR CONCENTRATOR DESIGNS BOTH FOR SPACE AND TERRESTRIAL USE INCLUDING OTHER SEMICONDUCTOR DEVICES AND ADVANCED OPTOELECTRONIC DEVICES.