Analytical drift-diffusion modeling of GaAs solar cells incorporating a back mirror

In this work we extend the analytical drift-diffusion model, or Hovel model, to model the electrical characteristics of solar cells incorporating a back mirror. We use a compact summation approach to derive modified optical generation functions in homojunction solar cells, considering both coherent and incoherent reflections from the back reflector. We use the model to simulate the performance of a real GaAs solar cell device fabricated using an epitaxial-lift-off procedure, demonstrating excellent agreement between the simulated and measured characteristics. We also calculate the performance of the same solar cell with different back reflectors, including metal mirrors and a distributed Bragg reflector.