Third generation multi-layer graded band gap solar cells for achieving high conversion efficiencies—II: Experimental results

New designs of multi-layer graded band gap solar cell structures were experimentally tested using well-understood AlxGa(1−x)As materials grown by the MOVPE technique. Laboratory scale devices (0.5 mm diameter) were processed and measured for their performance as solar cells. Both Voc (1110 mV) and fill factors (∼83%) for the best devices have shown drastic improvements over existing cells and the short-circuit current densities measured are in the range (10–20) mA cm−2 .