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

摘要

This article reports the quality of In _xGa _(1-x)As (0 < x < 0.2) layers grown on 15°-off GaAs substrate by metalorganic chemical vapor deposition. The crystalline quality of the In _xGa _(1-x)As epilayers is determined by x-ray reciprocal space mapping (RSM). From the RSM results, the crystalline quality of In _xGa _(1-x)As 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 In _xGa _(1-x)As epilayer is found to strongly depend on indium content. The photovoltaic performance of p-n structure In _(0.16)Ga _(0.84)As solar cell shows the lower device performance, because the In _xGa _(1-x)As 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/In _xGa _(1-x)As graded layer interface. The performance of In _(0.16)Ga _(0.84)As solar cell with p-n structure can be significantly improved by the p-i-n structure.