The kinetics of recombination of electrons and acceptor-bound holes in AlGaAs-GaAs heterostructure obey a single-exponential decay in the liquid phase of 2D electrons, whereas localization gives rise to a broad spectrum of recombination rates, especially in the magnetic freeze-out regime, This results in a power-law dependence I(t)(proportional to)(tau/t)(alpha) in the tail of the recombination kinetics, with the universal exponent alpha=(1 - nu)(-1) at nu<1 for all the samples examined experimentally in this work. (C) 1996 American Institute of Physics.