Atomic layer epitaxy (ALE) of GaAs is achieved in a relatively wide temperature range from 490 to 520 °C by using nitrogen carrier gas. For hydrogen carrier gas, the corresponding temperature range is only from 490 to 500 °C. The upper temperature limits for ALE correspond to the decomposition temperatures of TMG in each carrier gas. Gas analysis reveals that using nitrogen expands the temperature range by suppressing TMG decomposition.