Improved efficiency of a SiGe thin film solar cell structure using CNT charge collector layer

In this study, a sige (si(1−x)gex x=0.1) thin film solar cell structure based on the carbon nanotube (cnt) charge collector is proposed and simulated. the addition of the cnt layer to the cell structure has been proven to change aspects of its physical characteristics, specifically the efficiency of the solar cell. also, the performance of this cell is considering in present of two types of the cnt layers with sheet resistances of 128 ω/□ and 76 ω/□. according to the numerical simulation, the cell structure using cnt layer with sheet resistance of 128 ω/□ has better performance parameters. the efficiency of proposed structure is 27.72%, which is higher than conventional structures without cnt layer. furthermore, we optimize the structure by varying the thickness of the window, base, emitter, and substrate layers. the cell efficiency after this optimization reaches 30.63%. finally, the optimal ratio of the width of the metal contact to the total width of the cell was calculated with the aim of reducing the shadowing loss effect. we show that total cell width in the presence of the cnt layer can be increased up to 1000 μm for the metal contact width of 50 μm, and an efficiency of 30.9% is obtained after this optimization.