Interband emission energy in a dilute nitride quaternary semiconductor quantum dot for longer wavelength applications

Excitonic properties are studied in a strained Ga1−xInxNyAs1−y/GaAs cylindrical quantum dot. The optimum condition for the desired band alignment for emitting wavelength 1.55 µm is investigated using band anticrossing model and the model solid theory. The band gap and the band discontinuities of a Ga1−xInxNyAs1−y/GaAs quantum dot on GaAs are computed with the geometrical confinement effect. The binding energy of the exciton, the oscillator strength and its radiative life time for the optimum condition are found taking into account the spatial confinement effect. The effects of geometrical confinement and the nitrogen incorporation on the interband emission energy are brought out. The result shows that the desired band alignment for emitting wavelength 1.55 µm is achieved for the inclusion of alloy contents, y=0.0554% and x=0.339% in Ga1−xInxNyAs1−y/GaAs quantum dot. And the incorporation of nitrogen and indium shows the red-shift and the geometrical confinement shows the blue-shift. And it can be applied for fibre optical communication networks.

Variation of band offsets (conduction and valence band offset) as a function of Nitrogen alloy content in a GaInNAs/GaAs quantum dot is shown here. The offsets of ΔEc=0.542 eV and ΔEv=0.145 eV are obtained for the 1.55 µm quantum dot structure. It is found that the conduction band offset is greater than the valence band offset for all the concentration of N and In.Figure optionsDownload as PowerPoint slide