A memory device is disclosed. The memory device includes a bottom contact. The memory device also includes a memory layer connected to the bottom contact, where the memory layer has a variable resistance. The memory device also includes a top electrode on the memory layer, where the top electrode and the memory layer cooperatively form a heterojunction memory structure, where a first contact formed at an interface between the bottom contact and the memory layer is ohmic, and where a second contact formed at an interface between the memory layer and the top electrode is ohmic.