Coulombic effects of electron-hole plasma in nitride-based nanostructures

We study the Coulombic effects of electron-hole plasma on the ground and first excited energy levels and carrier wave functions in a GaN/AlGaN quantum well (QW) structure. The coupled Schrodinger equations for electron and hole states are solved self-consistently in the Hartree-Fock approximation along with the Poisson equation. As expected, the decreasing QW width and increasing plasma density diminish the charge separation in the QW induced by the internal field, leading to the relatively reduced contribution of the Hartree interaction to the energy-level shift. In contrast, the calculation also demonstrates that the contribution of many-body effects becomes more pronounced. The resulting competition between the many-body and Hartree contributions causes a nonmonotonous dependence of the electron and hole energies on the plasma density at a given field. These findings are applied to explore the potential bistable behavior in the QW electroabsorption under near-band-edge photoexcitation. (c) 2005 American Institute of Physics.