Material and device characterization of InGaP solar cells grown on GaAs misoriented substrates by metal-organic chemical vapor deposition

Abstract We grew and characterized Zn- and Si-doped In0.48Ga0.52P grown on (0 0 1) GaAs substrates misoriented by θS = 0°, 2°, 6°, and 10° toward (1 1 1)A using metal-organic chemical vapor deposition. The dopant incorporation efficiency is improved with higher θS because of a larger surface free energy. The lattice constant of InGaP is increased with higher doping concentration, whereas it is decreased with higher θS as a result of reduced CuPt-type ordering in InGaP. This reduced ordering with θS from 0° to 10° is supported by a bandgap increase of ~60 meV. The open-circuit voltage of InGaP solar cell with θS = 10° is more than 100 meV higher than that with θS = 2° due to the increased bandgap and the decrease of the ordering-related defects. Besides, a larger CuPt-type ordering results in a greater reduction of the thermal activation energy of InGaP solar cell.