Optical gain of compressively strained InGaAs/InP multiple quantum wires

Abstract

Optical properties of compressively strained InGaAs/InP vertically stacked multiple quantum wires (QWRs) are investigated using a six-band strain-dependent k . p Hamiltonian. The transition energy decreases with increasing number of wire layers due to the reduction in the subband energy in the conduction band. These results can be explained by the strain relaxation dependence on the number of wire layers. In the case of a one-wire layer, it is observed that the matrix element for the c(1)-v(1) transition is the same as that for the c(1)-v(2) transition. On the other hand, in the case of three- or five-wire layers, the matrix elements between the first conduction degenerate subbands and the first valence degenerate subbands are not the same because of the nonuniform distribution of the wavefunction over layers. The QWRs with three- and five-wire layers show about three and five times larger optical gain than that with one-wire layers. The peak wavelength is shown to be redshifted with increasing number of wire layers because of the strain relaxation.