TRANSPARENT AND CONDUCTIVE LAYERS USED FOR REDUCING OPTICAL REFLECTION LOSS FOR FABRICATING MECHANICALLY STACKED MULTI-JUNCTION SOLAR CELLS

Abstract

Reduction of optical reflection loss at the intermediate region for the mechanically stacked multi-junction solar cells is discussed. The top and bottom substrates are bonded using an adhesive dispersed with indium-tin-oxide particles. Transparent and conductive Indium-gallium-zinc-oxide (IGZO) and tin-dioxide (SnO2) layers are inserted between the adhesive and the substrates as anti-reflection layers. The optical reflectivity of GaAs and Si stacked sample well decreased by the insertion of 130-nm-thick IGZO layers. 157-nm-thick SnO2 layers also decreased the optical reflectivity of stacked sample. High effective absorbency of bottom substrates for the light incident angle between 0 and 50 was achieved for GaAs/Si stacked sample with IGZO layers.