Modeling the spectral response of the quantum well solar cell

• Published in: Journal of applied physics 1993-07, Vol.74 (1), p.614-621
• Main Authors: PAXMAN, M, NELSON, J, BRAUN, B, CONNOLLY, J, BARNHAM, K. W. J, FOXON, J. S, ROBERTS, J. S
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed Matter; Electronics; Exact sciences and technology; Optoelectronic devices; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.355275

The quantum well solar cell is an alternative to more conventional multiband gap approaches to higher cell efficiency. Preliminary studies have shown that the insertion of a series of quantum wells into the depletion region of a GaAs/AlxGa1−xAs p-i-n solar cell can significantly enhance the cell’s short-circuit current. We present here a model for the spectral response of GaAs and AlxGa1−xAs p-n and p-i-n solar cells, with and without quantum wells, based on a standard solution of the minority-carrier equations. Particular emphasis is placed on modeling the absorption coefficient of the AlxGa1−xAs and of the quantum wells. We find that our model can accurately predict the spectral response of a wide variety of cells: both conventional p-n junctions in GaAs and AlxGa1−xAs, and various geometries of quantum well solar cell in AlxGa1−xAs/GaAs (x∼0.3). We discuss the strengths and weaknesses of the model and its underlying assumptions, and conclude by using the model to design p-i-n quantum well solar cells with higher short-circuit current outputs.