A strain-balance multiquantum well (MQW) approach to enhance the GaAs solar cell efficiency is reported. Using a p-i-n diode structure, the strain-balanced GaAsP/InGaAs MQW is grown on a GaAs substrate and equals a good GaAs cell in terms of power conversion efficiency. The cell design is presented together with measurements of the forward bias dark current density, quantum efficiency, and 3000 K light-IV response. Cell efficiencies under standard air mass (AM) 1.5 and AM 0 illumination are projected from experimental data and the suitability of this cell for enhancing GaInP/GaAs tandem cell efficiencies is discussed.

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/Al_xGa_1−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 Al_xGa_1−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 Al_xGa_1−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 Al_xGa_1−xAs, and various geometries of quantum well solar cell in Al_xGa_1−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.