Gamma-ray irradiation effect on planar defect evolution of lattice-matched InGaAsN/GaAs/Ge grown by MOVPE

Abstract

This study explores structural changes in lattice-matched InGaAsN/GaAs/Ge films grown by MOVPE under gamma-ray irradiation. Exposure to a 60Co gamma rays at doses ranging from 0 to 2.0 MGy improved crystal uniformity by increasing surface grain size, reducing roughness from 8.328 nm to 3.512 nm. Planar defects in the GaAs layer traversed the InGaAsN layer, causing interface roughness. Electron diffraction patterns along the [110]-zone axis showed uniform alloy composition. TEM images revealed line contrasts at the GaAs/Ge interface extending into the InGaAsN layer, with boundary-like defects parallel to the growth direction. Additionally, (002) and (002) reflections, along with {111} planes, indicated planar defects, possibly antiphase boundaries. AFM and FESEM confirmed submicron-sized domains, characteristic of antiphase boundaries, in the InGaAsN film.