Influence of barrier height on carrier lifetime in Ga1-yInyP/(AlxGa1-x)1-yInyP single quantum wells.

Abstract

Using time-resolved photoluminescence, we have examined the photoluminescence (PL) decay time of ${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{In}}_{\mathit{y}}$P/(${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${)}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{In}}_{\mathit{y}}$P single quantum wells with various well widths and different Al content in the barriers. At low temperatures, we find an increase of the lifetime with increasing temperature in good agreement with the temperature dependence of radiative recombination. At a characteristic temperature, which depends on the quantum-well thickness, a drop of the PL lifetime is observed. The temperature dependence can be explained by simultaneous thermal emission of electrons and holes out of the quantum wells. We find that the activation energy ${\mathit{E}}_{\mathit{a}}$ is equal to one-half of the total confinement energy \ensuremath{\Delta}E of the electron-hole pair in the quantum well and can be explained on the basis of Boltzmann statistics assuming thermal equilibrium between quantum-well and barrier states during the recombination.