Enhancement of GaAs solar cell performance by using a ZnO sol–gel anti-reflection coating

• Coupling ZnO sol–gel to GaAs p–n junction solar cell.
• Enhancement in the device performance better that 30%.
• An enhancement, after utilizing the ZnO anti-reflection coating, was observed on the order of 32%, 38, and 51% for the power conversion efficiency, spectral response, and quantum efficiency, respectively.
• ZnO sol–gel was annealed at a low temperature (150 °C) to avoid the breakdown of the p–n junction and to prevent the degradation of the ohmic contacts.

The performance of a GaAs p–n junction solar cell was investigated by coating the device with 110 nm thick ZnO sol–gel anti-reflection film. A post-furnace thermal annealing at 150 °C for 30 min was performed on the ZnO film after it was spin coated on the device with a speed of 8000 rpm. Ellipsometry was used to measure the reflectance, thickness, and the refractive index of the ZnO film. The solar cell performance was investigated by using the current–voltage technique from which the power conversion efficiency was extracted. The spectral response and quantum efficiency were also measured for the solar cell. An enhancement, after utilizing the ZnO anti-reflection coating, was observed on the order of 32%, 38, and 51% for the power conversion efficiency, spectral response, and quantum efficiency, respectively.