Design of AlxGa1−xAs/GaAs/InyGa1−yAs triple junction solar cells with anti-reflective coating. (September 2015)

• Record Type: Journal Article
• Authors: Bernal-Correa, Roberto; Morales-Acevedo, Arturo; Pulzara Mora, Álvaro; Montes Monsalve, Jorge; López López, Máximo
• Is Part Of: Materials science in semiconductor processing. Volume 37(2015:Sep.)
• Page Start: 57
• Page End: 61
• Publication Date: 2015-09
• Subjects: Tandem solar cells -- III–V Semiconductors -- Anti-reflective coatings; Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2015.01.020
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: Multi-junction solar cells (SC) made from III–V compound semiconductors are still in the development phase. Here, we perform calculations for multi-junction cells: Al x Ga1− x As top junction, GaAs middle junction and In y Ga1− y As bottom junction (all of these materials with band-gaps between 2.1 and 0.8 eV) in order to obtain the optimal band gap and thickness for each junction under the AM1.5 solar radiation spectrum. The ideal photo-current density is around 15.5 mA/cm 2 . In order to reduce the natural reflectivity, an anti-reflective coating (ARC) was chosen, based on a MgF2 /ZnS double layer, allowing for a significant increase of the current density with respect to a cell without it. Calculations of external quantum efficiency (QE) were also performed for the three cases mentioned above: ideal one, taking into account the total reflection and with the ARC double layer. Finally, when more realistic calculations are done, taking into account the carrier recombination at each sub-cell, and the light reflection for a tandem cell with the designed ARC on top, the expected conversion efficiency ( η ), under the AM 1.5 spectrum (without concentration), was determined to be around 38.5%, making this an attractive III–V compound tandem cell to be investigated in the near future.