Gallium content enhancement in CuIn/sub 1-x/Ga/sub x/Se/sub 2/ thin films prepared by two-selenizations process using Se vapor solar cells

摘要

Gallium content in CuIn/sub 1-x/Ga/sub x/Se/sub 2/ thin film solar cells prepared by a two-selenization process using Se vapor has been enhanced by optimizing the metallic layer sequence and selenization parameters. Maintaining a high selenium vapor incidence rate of /spl ges/50 /spl Aring/ s/sup -1/ increased the Ga content x in the formula CuIn/sub 1-x/Ga/sub x/Se/sub 2/ from 0.06 to 0.11. Fast temperature rise of 50-90/spl deg/C min/sup -1/ and controlled cooling-down rate to 300/spl deg/C with a lower Se vapor incidence rate increased the Ga content still further. CuIn/sub 1-x/Ga/sub x/Se/sub 2/ thin-film solar cells having Ga content x of 0.18 showed an open-circuit voltage V/sub oc/ of 451.8 mV, a short-circuit current density J/sub sc/ of 34.5 mA, a fill factor of 57.87%, and a total-area efficiency of 9.02% with a fairly constant spectral response. The results are significant because the process can be easily scaled up for economic manufacture.