Mediated Exciton In The Electricity Sub-well Wires

Exciton states in quantum wells and wires formed by semiconductor heterostructure have attracted great attention during the past three decades. With the recent advances in the epitaxial crystal-growth techniques such as mental-organnic chemical vapor deposition and molecular-beam epitaxy, low-dimensional semiconductor system was applied broadly. Impurity have an important effect on transmission of electron and optical properties of material, studies of the electronic and impurity states in a low-dimensional semiconductor have in the past few years attracted considerable attention.However, in these intensive investigations the image potential due to the dielectric mismatch inside and outside the quantum well is neglected because of the weak effect of image charge. In the recently, years, with the advances in the crystal-growth techniques the superlattices can be grown with two kind of mismatched materials. For this kind of superlattic, the effect of image charge will can't be neglected.On the basis of the former research, in the effective mass approximation, at first we calculate the exciton ground statebinding energy in infinite GaAs/Ga_1-XAl_xAs(x = 0.4)quantum wellwire. In calculation, we consider the effect of image potential due to the dielectric mismatch inside the quantum well wire, theresults we calculated is compared with the results of quantum well, with the consideration of the image potential, the binding energy of the ground state of an exciton in an infinite dielectric quantum well wire, subjected to an external electric field is studied by means of the variational technique. The influence of the image potential is obtained as one function of the well width and the electric field strength.We have a conclusion as follows:(1) The results are more interesting and that the image potential is more important than the results of quantum well.(2) The effect of the self-image potential on exciton ground binding energy is very small, which can be neglected in calculation.(3) Subjected to an external electric field, the effects of self-image-potential and mutual-image potential on the stark shift are just opposed.