A programmable metallization 
cell ("PMC") comprises a 
fast ion conductor such as a 
chalcogenide-
metal ion and a plurality of electrodes (e.g., an 
anode and a 
cathode) disposed at the surface of the 
fast ion conductor and spaced a 
set distance apart from each other. Preferably, the 
fast ion conductor comprises a 
chalcogenide with Group IB or Group IIB metals, the 
anode comprises silver, and the 
cathode comprises aluminum or other conductor. When a 
voltage is applied to the 
anode and the 
cathode, a non-volatile 
metal dendrite grows from the cathode along the surface of the fast 
ion conductor towards the anode. The growth rate of the 
dendrite is a function of the applied 
voltage and time. The growth of the 
dendrite may be stopped by removing the 
voltage and the dendrite may be retracted by reversing the 
voltage polarity at the anode and cathode. Changes in the length of the dendrite affect the resistance and 
capacitance of the PMC. The PMC may be incorporated into a variety of technologies such as memory devices, programmable 
resistor / 
capacitor devices, optical devices, sensors, and the like. Electrodes additional to the cathode and anode can be provided to serve as outputs or additional outputs of the devices in sensing electrical characteristics which are dependent upon the extent of the dendrite.