A system or apparatus including an N-type transistor structure including a gate electrode formed on a substrate and source and drain regions formed in the substrate; a contact to the source region; and a pinning layer disposed between the source region and the first contact and defining an interface between the pinning layer and the source region, wherein the pinning layer has donor-type surface states in a conduction band. A method including forming a transistor structure including a gate electrode on a substrate and source and drain regions formed in the substrate; depositing a pinning layer having donor-type surface states on the source and drain regions such that an interface is defined between the pinning layer and the respective one of the source and drain regions; and forming a first contact to the source region and a second contact to the drain region.