Dynamic properties of radiative recombination inp-typeδ-doped layers in GaAs

Abstract

We present an optical study of thin Zn-doped GaAs layers embedded in bulk GaAs, grown by metal-organic vapor-phase-epitaxy by means of stationary and time-resolved optical spectroscopy. The concentration of the Zn acceptors was aimed at $2\ifmmode\times\else\texttimes\fi{}{10}^{20}/{\mathrm{cm}}^{3}$ in 4-nm-wide doping regions. The intensity of the optical radiative transition (so called the F emission) appearing in photoluminescence spectra was found to be related to holes confined at doping regions. The F emission shows a strong dependence on excitation intensity and temperature. The energy position varies from 1.46 to 1.49 eV as the excitation density changes from about 40 $\mathrm{mW}/{\mathrm{cm}}^{2}$ to 23 $\mathrm{W}/{\mathrm{cm}}^{2}.$ The dynamic properties of the F-emission band have been studied by time-resolved spectroscopy. The F emission shows a nonexponential decay character. The decay time of the F emission exhibits a strong dependence on the detection energy within the F-emission band. The decay time becomes longer as the detection energy is redshifted.