GaAs quantum well-dots solar cells with spectral response extended to 1100 nm

Expanding the photosensitivity spectrum of a single-junction GaAs-based solar cell to 1100 nm by using InGaAs hybrid quantum well dots (QWDs) multilayer media is reported. This nanostructure represents an In_0.3Ga_0.7As quantum wells with modulation of thickness and composition. Up to 15 QWD layers alternated with GaAs spacers can be inserted in an i-region of the GaAs p-i-n junction without impairing its crystal quality and quantum efficiency in spectral interval of GaAs absorption. The QWD layers are responsible for appearance of a longer wave spectral response (900-1100 nm). A photocurrent increment as high as 4.6 (5.2) mA/cm² for terrestrial (space) spectrum is demonstrated.