Effects of insertion of strain-engineering Ga(In)NAs layers on optical properties of InAs/GaAs quantum dots for high-efficiency solar cells

• Improvement in surface density of strain compensated InAs/GaNAs/GaAs quantum dots by insertion of strain mediating GaInNAs layers.
• Enhancement in luminescence efficiency of strain compensated InAs/GaNAs/GaAs quantum dots by insertion of strain mediating GaInNAs layers.
• Significant red shift (>1200 nm) of spectral response of InAs/GaNAs/GaAs quantum dot solar cells by insertion of strain engineering GaInNAs layers.

We report study on stacked InAs/GaNAs quantum dots heterostructures with dilute nitride GaInNAs strain mediating layers embedded in GaAs p-i-n solar cell structure. The insertion of GaInNAs strain mediating layers in the vicinity of the strain compensated InAs/GaNAs quantum dots heterostructures enhances their surface density, improves and significantly red shifts their light emission. Embedding a stack of the strain-mediated InAs/GaInNAs/GaNAs quantum dots in the i region of a GaAs p-i-n solar cell leads also to a red shift of the absorption edge of the solar cells and improves the solar cell photogenerated currents at longer wavelengths beyond 1200 nm.