| In the effective mass approximation, the binding energies of exciton and excitonic complexes(charged exciton and biexciton) in GaAs quantum well-wires are studied by using the one-dimensional potential model. The Hamiltonian of the systems are simplified by using the equivalent potential model, then the eigenvalue problem for the simple Hamiltonian can be treated with efficient finite-difference method and the binding energies of the systems can be achieved. The present results agree fairly well with the previous experimental and theoretical results.In the paper, we calculate the binding energies of excitons and excitonic complexes in the quantum well-wires as functions of electron and hole confinement length, and we also calculate the magnetic field dependence of the binding energies of excitons and excitonic complexes, when the magnetic field parallels to the axis of the quantum well-wires.In the end, the results are discussed and compared in detail with previous experimental and theoretical results. The conclusions are as follows:(1) The difference of the binding energies between the positive charged exciton(X+) and the negative charged exciton(X-) is related with the electron and hole confinement. X+ is more stable than X- in the case of equal hole and electron confinement, While the confinement is different, a crossing of the binding energy lines of X+ and X- as functions of the hole oscillator lengths has been found. A stronger hole confinement within quantum well-wires enhances the hole-hole interaction and induces the binding energy of X- larger than that of X+.(2) The ratio of the binding energy of biexciton to that of exciton is from 0.18 to 0.30 for different hole confinements, which is conformed with the ones obtained from theory and experiment previously.(3) The binding energies of exciton and excitonic complexes enhance as the magnetic field increases, and when the hole and electron oscillator length is different, the influence of the magnetic field is different. |
PDF Full Text Request