Multiband GaNAsP quaternary alloys

Abstract

We have synthesized GaNxAs1−yPy alloys (x∼0.003−0.01 and y=0–0.4) using nitrogen (N) ion implantation into GaAsP epilayers followed by pulsed laser melting and rapid thermal annealing techniques. As predicted by the band anticrossing model, the incorporation of N splits the conduction band of the GaAs1−yPy substrate, and strong optical transitions from the valence band to the lower (E−) and upper (E+) conduction subbands are observed. The relative strengths of the E− and E+ transition change as the localized N level EN emerges from the conduction band forming narrow intermediate band for y>0.3. The results show that GaNxAs1−x−yPy alloys with y>0.3 is a three band semiconductor alloy with potential applications for high-efficiency intermediate band solar cells.