We study the layer state of a binary mixture of end-grafted polymer layer by generalizing the Alexander model to allow for the possibility of a layer structure. We find that for an asymmetric mixture, the minority chains stay close to the grafting wall and the difference in layer heights of the two components scales as Nsigma1/3 where N is the chain length and sigma is the total surface coverage. The layer heights of the system as a function of the incompetibility and the relative fraction of the two types of chains are obtained.
