Memristors with asymmetric electrodes

Abstract

Embodiments of the present invention are directed to nanoscale memristor devices that provide nonvolatile memristive switching. In one embodiment, a memristor device comprises an active region, a first electrode disposed on a first surface of the active region, and a second electrode disposed on a second surface of the active region, the second surface opposite the first surface. The first electrode is configured with a larger width than the active region in a first direction, and the second electrode is configured with a larger width than the active region in a second direction. Application of a voltage to at least one of the electrodes produces an electric field across a sub-region within the active region between the first electrode and the second electrode.

1 - 15 . (canceled) 
     
     
         16 . A memristor device, comprising:
 an active region;   a first electrode disposed on a first surface of the active region, the first electrode configured with a smaller width than the active region in a first direction; and   a second electrode disposed on a second surface of the active region, the second surface opposite the first surface and the second electrode configured with a larger width than the active region in a second direction, wherein application of a voltage to at least one of the electrodes produces an electric field across a sub-region within the active region between the first electrode and the second electrode; and   a patterned opening in at least one of the electrodes, the patterned opening comprising multiple edges and concentrating the electric field within the sub-region.   
     
     
         17 . The memristor device of  claim 16 , wherein the patterned opening resembles a four-leaf clover. 
     
     
         18 . The memristor device of  claim 16 , wherein the multiple edges are located over the sub-region. 
     
     
         19 . The memristor device of  claim 16 , wherein the active region retains a state after a drift field resultant from the application of the voltage is removed. 
     
     
         20 . The memristor device of  claim 16 , wherein at least one of an interface connecting the active region to an electrode is non-covalently bonded. 
     
     
         21 . The memristor device of  claim 16 , further comprising an electronic barrier at an interface between the active region and at least one electrode. 
     
     
         22 . The memristor device of  claim 16 , wherein the active region comprises a combination of two or more semiconductor layers. 
     
     
         23 . The memristor device of  claim 22 , wherein a boundary between the two or more semiconductor layers is moveable. 
     
     
         24 . A crossbar comprising:
 a first layer of substantially parallel nanowires;   a second layer of substantially parallel nanowires overlaying the first layer of nanowires; and   at least one nanowire intersection forming a memristor device, each memristor device including an active region disposed between a nanowire in the first layer and a second nanowire in the second layer;   wherein:
 the active region comprises a sub-region between the first electrode and the second electrode; 
 the nanowire in the second layer is configured with a larger width than the active region in a first direction and the nanowire in the first layer is configured with a smaller width than the active region in a second direction; and 
 application of a voltage to at least one of the first and second nanowires produces an electric field across the sub-region extending into a portion of the active region that surrounds the sub-region. 
   
     
     
         25 . The crossbar of  claim 24 , wherein the active region comprises a primary active region to transport dopants that control a flow of charge carriers. 
     
     
         26 . The crossbar of  claim 25 , wherein the active region further comprises a secondary active region that is a film. 
     
     
         27 . A memristor device, comprising:
 an active region;   a first electrode disposed on a first surface of the active region, the first electrode configured with a smaller width than the active region in a first direction; and   a second electrode disposed on a second surface of the active region, the second surface opposite the first surface and the second electrode configured with a larger width than the active region in a second direction, wherein application of a voltage to at least one of the electrodes produces an electric field across a sub-region within the active region between the first electrode and the second electrode;   a first patterned opening in the first electrode; and   a second patterned opening in the second electrode, the first and second patterned openings to concentrate the electric field within the sub-region.   
     
     
         28 . The memristor device of  claim 27 , wherein at least one of the first patterned opening and the second patterned opening comprising at least two edges. 
     
     
         29 . The memristor device of  claim 27 , wherein a resistance of the memristor device is controlled at an interface between the active region and an electrode. 
     
     
         30 . The memristor device of  claim 27 , wherein a resistance of the memristor device is controlled within a bulk material of the active region.