Multiband GaNAsP quaternary alloys

We have synthesized GaNxAs1-yPy alloys (x similar to 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 E-N 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.