Dimensionality dependence of the band-gap renormalization in two- and three-dimensional electron-hole plasmas in GaAs

We have investigated the band-gap renormalization due to many-body effects in electron-hole plasmas in 2D GaAS-GaAlAs multiple quantum-well structures. A comparison of these data with corresponding 3D data and calculations for both dimensionalities shows that the band-gap shift increases absolutely but decreases in effective Rydberg units with decreasing dimensionality. The dimensionality dependence of the band-gap shift is traced to different screening efficiencies in 3D and 2D systems.