Abstract:
High efficiency photovoltaic devices are based both on the ill-V compounds and silicon semiconductor technologies. These devices are of both single and multijunction configurations. A tandem solar cell including more than two junctions is one of the candidates for photovoltaic cell.
Among many material systems, the AIGaAs/Si monolithic tandem solar cell is attractive for its high efficiency, low cost and large-area photovoltaic cell from the band-gap-energy point ofview.
The aim of this work is focused on semiconducting materials in Si and AlxGa'_xAs on the Si substrate and the AIGaAs/Si monolithic tandem solar cell. The optimum efficiency is determined taking into
account the different factors affecting the photogenerated current, open circuit voltage and fill factor. The most considerable subject of this study in the top cell is its emitter region. The judicious choice of aluminium content of the AIGaAs layer is the particular considered point, because results reveal that efficiency decreases with increasing AI composition. Also the thickness and doping concentration are examined. Shallow and highly doped emitter improve the efficiency High doping level effects in Si solar cells (the bottom cell) in the two regions particularly in the base are
investigated taking into account the free carrier absorption. these improve considerably the open voltage and efficiency. Since, the AlGaAs/Si tandem solar cells are promising for both terrestrial and space applications, it is the object of this work to perform modeling studies in one dimension and to
determine their maximum attaignable global and AMO efficiencies. Modeling and simulation are performed using PC 1 D simulator.
