Electronic band structures of GaInAsP/InP vertically stacked multiple quantum wires with strain-compensating barriers

Abstract

Energy-band structures of compressively strained GaInAsP/InP quantum wires fabricated by etching and regrowth method have been calculated using an 8 band k⋅p theory including strain relaxation. The effects of strain-compensating barriers and vertically stacking multiple wire layers on band structures are investigated. It is found that due to the dependence of strain relaxation on the amount of strain compensation in barrier regions and on the number of wire layers in the vertical stack, unlike strained quantum films, the energy-band structures of strained quantum wires are dependent on these factors. Experimentally observed wire-width dependence of the large energy blueshift in vertically stacked multiple quantum-wire structures is accurately explained using our calculations without any fitting parameter. Additional broadening in the emission spectra due to vertically stacking multiple quantum wires is found to be negligible. Our results show that strain compensation in barrier layers may be used effectively as an additional parameter to optimize practical device design.