Crystalline quality and photovoltaic performance of InGaAs solar cells grown on GaAs substrate with large-misoriented angle

This article reports the quality of InxGa1−xAs (0 < x < 0.2) layers grown on 15°-off GaAs substrate by metalorganic chemical vapor deposition. The crystalline quality of the InxGa1−xAs epilayers is determined by x-ray reciprocal space mapping (RSM). From the RSM results, the crystalline quality of InxGa1−xAs epilayers grown with small indium composition (x < 0.11) is better than that of large indium composition (x > 0.11) due to the small strain relaxation. The crystalline quality of InxGa1−xAs epilayer is found to strongly depend on indium content. The photovoltaic performance of p–n structure In0.16Ga0.84As solar cell shows the lower device performance, because the InxGa1−xAs films grown on 15°-off GaAs substrate show a large strain relaxation in the active layer of solar cell. It results in dislocation defects created at the initial active layer/InxGa1−xAs graded layer interface. The performance of In0.16Ga0.84As solar cell with p–n structure can be significantly improved by the p–i–n structure.

► Quality of InxGa1-xAs grown on GaAs substrate is affected by strain relaxation of InxGa1-xAs epilayer.
► Performance of solar cells is strongly influenced by p–n and p–i–n structures.
► Performance of In0.16Ga0.84As solar cell with p–n structure can be significantly improved by the p–i–n structure.