Investigations on AlₓGa_ 1-xAs Solar Cells Grown by MOVPE

Solar cells based on AlxGa1-xAs in its direct bandgap range were fabricated and analyzed. We show that state-of-the-art metalorganic vapor phase epitaxy systems and precursors are capable of growing AlxGa1-xAs solar cells with defect concentrations up to 1 × 1014cm-3and less determined by deep level transient spectroscopy. However, for the n-doped material, inevitable DX-centers exist. These dopant-related defects limit the performance of the investigated AlxGa1-xAs solar cells with x ≥ 0.20. To overcome this issue, the n-doped AlxGa1-xAs As emitter can be replaced by an n-doped Ga0.51In0.49P heteroemitter. This heterojunction solar cell again shows overall defect concentrations below 1 × 1014cm-3and significantly improved cell characteristics.