Selective formation of an efficient Er-O luminescence center in GaAs by metalorganic chemical vapor deposition under an atmosphere containing oxygen

Abstract

To investigate the effects of oxygen codoping on Er luminescence centers in GaAs, we grew Er-doped GaAs by low-pressure metalorganic chemical vapor deposition (MOCVD) and measured the photoluminescence spectrum due to the intra-4f-shell transition of Er. The spectrum of a sample grown in a pure hydrogen atmosphere was complicated, showing many lines and bands. The spectrum of a sample grown in a hydrogen atmosphere containing 0.2 ppm oxygen, on the other hand, was simple and had few lines. The spectrum of the oxygen-codoped sample showed higher peak intensities as well as higher integrated luminescence intensity in the 1.5–1.6 μm region. Secondary-ion mass spectroscopy revealed that the oxygen-codoped sample had a higher concentration of oxygen, indicating the formation of an Er-O complex center. One kind of optically active efficient Er-O complex luminescence center can, therefore, be selectively formed under suitable MOCVD growth conditions.