18.7 % efficient (1-sun, AM0) large-area GaAs solar cells

AlGaAs-GaAs heteroface solar cells with areas of 4 cm2 have been fabricated by metalorganic chemical vapor deposition. One-sun, AM0 efficiencies as high as 18.7% and 18.4% have been obtained for p-n and n-p structures, respectively. Both kinds of cell structures are characterized by excellent external quantum efficiencies and their performance is close to that predicted by a realistic computer model. In agreement with the computer model, the n-p cell exhibits a higher short-circuit current density because of its thin, n-type top absorber.