Luminescence-Time-Response Measurements and the Strength of Hole Capture at the Zn-O Impurity Complex in GaP

The influence of multiple trapping by sulfur donors on the luminescence time response at Zn-O and oxygen recombination centers in GaP is studied in the range 4-120°K. A value of 3(±1) × ${10}^{-10\mathrm{}}$ ${\mathrm{cm}}^2$ is deduced for the electron-capture cross section of sulfur donors. From a comparison of the 4880- and 5682-Å excited time decay, an upper bound of 5(±2)×${10}^{-17\mathrm{}}$ ${\mathrm{cm}}^2$ is obtained for the hole-capture cross section of the Zn-O complex in a crystal with a net acceptor concentration of 2×${10}^{17}$ ${\mathrm{cm}}^{-3\mathrm{}}$. Recent impulse-time-response measurements in GaP: Zn-O are reinterpreted in terms of multiple trapping by shallow (26-meV) electron traps.