NOVELTY - The solar cell comprises subcells comprising a base semiconductor layer (30) having a first bandgap, an emitter semiconductor layer (34) having a second bandgap and a first depletion semiconductor layer (32), and a second depletion semiconductor layer (33). The first depletion semiconductor layer: is positioned between the base semiconductor layer and the emitter semiconductor layer; has a third bandgap and a second cross-sectional thickness; eclipses a depletion region; and comprises a third semiconductor composition. The third bandgap is 1.5% greater than the first and second bandgaps.    USE - Used as a solar cell such as heterojunction solar cells and a multi junction solar cell such as a gallium arsenide solar cell or an inverted metamorphic solar cell.    ADVANTAGE - The solar cell exhibits high power conversion efficiency and current output.    DETAILED DESCRIPTION - The solar cell comprises subcells comprising a base semiconductor layer (30) having a first bandgap, an emitter semiconductor layer (34) having a second bandgap and a first depletion semiconductor layer (32), and a second depletion semiconductor layer (33). The first depletion semiconductor layer: is positioned between the base semiconductor layer and the emitter semiconductor layer; has a third bandgap and a second cross-sectional thickness; fully eclipses a depletion region; and comprises a third semiconductor composition. The third bandgap is 1.5% greater than the first and second bandgaps. The base semiconductor layer and the first depletion semiconductor layer comprise a p-type semiconductor material. The emitter semiconductor layer and the second depletion semiconductor layer comprise an n-type semiconductor material. The second depletion semiconductor layer is positioned between the first depletion semiconductor layer and the emitter semiconductor layer. The base semiconductor layer and the emitter semiconductor layer define: the depletion region having a first cross-sectional thickness; and a p-n junction. The second cross-sectional thickness is equal to the first cross-sectional thickness. The base semiconductor layer comprises a first semiconductor composition. The emitter semiconductor layer comprises a second semiconductor composition. The first semiconductor composition is same as the second semiconductor composition. The third semiconductor composition is different than the first and second semiconductor compositions. Each of the base, the depletion and the emitter semiconductor layers comprise a Group III-V alloy. The second bandgap is greater than the first bandgap.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of a subcell.    Base semiconductor layer (30)    First depletion semiconductor layer (32)    Second depletion semiconductor layer (33)    Emitter semiconductor layer (34)    Window. (36)