Analysis of the suitability of Al_xGa_1-xAs as active material in III-V multiple-junction solar cells

In the past, Al_xGa_1-xAs single and multiple-junction solar cells have been manufactured and tested. Although the ternary Al_xGa_1-xAs is one of the most studied semiconductor systems, the results have often lagged behind expectations. In the thesis presented here, for the first time, the deep understanding of the Al_xGa_1-xAs material system resulting from material analysis was linked with its application in solar cells. As has been shown, many cell results can only be explained if the peculiarities of the material, in particular the formation of DX centers and the transition from direct to indirect semiconductor, are also included. From this purposeful consideration of the material in terms of its usefulness in the semiconductor device and the technological significance of individual properties, not only high-quality solar cells based on Al_xGa_1-xAs were produced but also new insights into the material properties of (Al_yGa_1-y)_1-zIn_zAs and the information gain from photoluminescence measurements can be significantly increased.