In this study, photoluminescence (PL) measurements are performed for analyzing shallow acceptor states in undoped cadmium telluride lms on gallium arsenide substrates. PL and time-resolved photoluminescence spectra are analyzed in the vicinity of a 1.55 eV band. The residual impurity concentration in the undoped cadmium telluride lm is greater than 1.5 × 10 18 cm −3 . By analyzing the peak shift of the 1.55 eV band as a function of time after pulsed excitation, the bound-tobound reaction constant for the undoped cadmium telluride lm on a gallium arsenide substrate is estimated to be 2.4 × 10 7 s −1 .