We report a theoretical investigation of carrier trapping in GaAs v‐groove quantum wire structures. Our results show that trapping is fast in wires confined by AlGaAs alloy barriers where the growth process creates a Ga‐rich vertical quantum well at the center of the v‐groove: this acts as a highly effective scattering channel into quantum wires states. The results indicate that with suitable growth engineering, high‐efficiency quantum wire structures can be obtained. ©1996 American Institute of Physics.