Tunable voltage margin access diodes

A method of tuning a voltage margin of an access diode during fabrication comprising:

• adjusting a bandgap of the access diode by varying a number of layers of a mixed electronic-ionic conduction (MIEC) material used to electrically connect a first electrode and a second electrode, wherein the MIEC material are above and in direct contact with a carbon doped silicon germanium substrate, and wherein the first electrode and the second electrode are above and in direct contact with MIEC material;
• and
• adjusting defect energy and effective mass of the access diode by doping the MIEC material with a conductive defect dopant, wherein doping the MIEC material with the conductive defect dopant comprises:
• interstitial or substitutional doping a lattice structure of the MIEC material with copper.

An access diode structure having a tunable voltage margin comprising:

• a mixed electronic-ionic conduction (MIEC) layer above and in direct contact with a carbon doped silicon germanium substrate, the MIEC layer comprising one or more individual layers of MoS2;
• a conductive defect dopant in a lattice structure of the MIEC layer, the conductive defect dopant comprising copper;
• a first electrode above and in direct contact with the MIEC layer;
• and
• a second electrode above and in direct contact with the MIEC layer, the second electrode separated from the first electrode by a lateral portion of the MIEC layer.