<p>A system (100) used as a selector in an RRAM array includes: a first metal (110)/semiconductor (or low bandgap dielectric) (120) structure, and a second metal (150)/semiconductor (or low bandgap dielectric) (140) structure. Also, the system includes an insulator (130). The insulator (130) is located between the first metal (110)/semiconductor (or low bandgap dielectric) (120) structure and the second metal (150)/semiconductor (or low bandgap dielectric) (140) structure and forms a metal (110)/semiconductor (or low bandgap dielectric) (120)/insulator (130)/semiconductor (or low bandgap dielectric) (140)/metal (150) structure to make the first and the second metal/semiconductor (or low bandgap dielectric) structures to face each other.</p>
