Optical properties of excitons in semiconductor (InP)-insulator quantum wires

Features in the spectra of absorption, luminescence, and luminescence efficiency obtained under sample excitation with differently polarized laser radiation, and the nonlinear dependence of the luminescence intensity on the excitation level are explained as due to excitonic transitions in semiconductor (InP)-insulator (chrysotile asbestos) quantum wires. The measured excitonic-transition energies in the quantum wires are in quantitative agreement with calculations. The calculations took into account both the size quantization in a quasi-one-dimensional structure and the “dielectric enhancement” of excitons (the noticeable increase of the exciton binding energy and of the excitonic-transition oscillator strength associated with the increased attraction between the electron and the hole due to the large difference between the dielectric permittivities of the semiconductor and the dielectric matrix).