MBE growth of 1 eV GaNAs/InGaAs superlattice with various periods thicknesses and corresponding photovoltaic response

The influence of periodic thickness on 1 eV GaNAs/InGaAs superlattices with high N content by MBE is in detail investigated. HRXRD and TEM measurements show that GaNAs/InGaAs superlattices display better periodic repeatability and interface quality when the periodic thickness increases from 6 nm to 20 nm. However, when it increases to 30 nm, the structural quality of the superlattice is degraded, which could be ascribed to ion damage during the growth of thick superlattice layers. The growth phenomenon above is modeled and analyzed. The well-optimized GaNAs/InGaAs superlattices are annealed and fabricated into the solar cell using a GaAs p-i-n structure in which the intrinsic region is the superlattice layers. The cell devices show the short-circuit current density of over 10 mA/cm2 under AM1.5 light illumination.