RADIATIVE LIFETIMES IN n-TYPE GALLIUM ARSENIDE

Abstract
Radiative lifetimes and time‐resolved spectra have been obtained for high‐purity n‐type gallium arsenide at low temperatures. The ∼ 1.51‐eV bands, generally associated with the annihilation of free and bound excitons, decay very rapidly, τ < 15 nsec. The 1.49‐eV band, variously described as donor‐acceptor recombination or as a free‐to‐bound recombination, has a longer nonexponential decay. For this band, the time‐resolved spectra show a steady shift to lower energy as the delay after the pulse is lengthened. The conclusion drawn is, that the 1.49‐eV band arises from a D‐A recombination process.