Efficiency Improvement of InGaP/SiGe tandem solar cell using Si0.18Ge0.82 graded buffer regions

Subject Areas : Journal of Optoelectronical Nanostructures

Mojtaba Shahraki ¹ , Majid Ghadrdan ²

1 - University of Sistan and Baluchestan
2 - University of Sistan and Baluchestan

Received: 2024-03-24 Accepted : 2024-06-01 Published : 2024-06-19

Keywords: Efficiency (Eff), Graded Buffer, Open Circuit Voltage (Voc), Short Circuit Current Density (Jsh),

Abstract :

In this paper, the effect of SiGe graded buffers on the performance of an InGaP/SiGe tandem solar cells is investigated. It is shown that, by the proper design of graded buffer layers, the efficiency of solar cells can be improved considerably. The proposed structure consists of an InGaP top cell and a SiGe bottom cell, which are separated by a tunnel junction and a window layer. Each part has a BSF layer and graded buffers are used between window and bottom cell as well as the bottom cell and the substrate.
Different parameters of the solar cell, involving photogeneration rate, electric field and the built-in potential, are calculated. Using the PSO algorithm for the proposed solar cell, the optimized dimensions and doping are determined to reach the maximum efficiency. The short circuit current density (Jsh) of 21.5 mA/cm2, Open circuit voltage (Voc) of 2.14 V, efficiency (η) of 38.18% and fill factor (FF) of 83% are obtained, which show the applicable improvement compared to other works.