Growth, Fabrication, and Characterization of InGaAsN Double Heterojunction Solar Cells

In this paper, we have demonstrated fabrication and characterization of p-GaAs/i-InGaAsN/n-GaAs double heterojunction solar cells (DHJSCs). The intrinsic InGaAsN absorption layers which were lattice-matched to GaAs substrate with photoresponse to 1 eV were grown by the metal organic chemical vapor deposition method. The samples were studied experimentally by varying the growth temperature of intrinsic InGaAsN absorption layers. By adjusting the indium and nitrogen content, we have grown InGaAsN epilayers which were lattice-matched to GaAs substrate at various growth temperatures. Among three intrinsic layer growth temperatures, it was found that the InGaAsN DHJSC with the intrinsic layer growth temperature of 550 °C can get the largest absorption region. Under the AM 1.5 direct spectrum, the DHJSCs with absorption layer which were grown at 550 °C have open-circuit voltages ranging from 0.295 V, short-circuit currents of 14.4 mA/cm2, and fill factor of 51.2%. The conversion efficiency of InGaAsN double heterojunction solar cells achieves 2.38%, and the absorption wavelength region would extend to 1200 nm.