A method of producing an electronic device precursor

A method of producing an electronic device precursor, the method comprising:

• (I) providing a substrate having a graphene layer structure on and across a surface thereof;
• (II) forming a first layer of dielectric material on and across the graphene layer structure by ALD;
• (III) forming a first patterned resist on the first layer of dielectric material to provide one protected region of dielectric material and underlying graphene, and a plurality of unprotected regions of dielectric material and underlying graphene;
• (IV) etching away the plurality of unprotected regions to expose corresponding portions of the substrate and thereby define one first region of dielectric-material-capped graphene layer structure having a plurality of exposed edges and to define contact portions adjacent the one or more exposed edges;
• (V) forming ohmic contacts in the contact portions;
• (VI) exposing the dielectric material of the dielectric-material-capped graphene layer structure region by removing substantially all resist material;
• (VII) forming a second patterned resist on the first region of dielectric-material-capped graphene layer structure, and optionally the ohmic contacts, to provide at least one protected region of dielectric material and underlying graphene adjacent a plurality of the ohmic contacts, and at least one unprotected region of dielectric material and underlying graphene;
• (VIII) etching away the at least one unprotected region to expose one or more corresponding portions of the substrate and thereby define at least one second region of dielectric-material-capped graphene layer structure having a plurality of exposed edges whereby each ohmic contact remains adjacent an edge of the at least one second region of dielectric-material-capped graphene layer structure;
• (IX) exposing the dielectric material of the at least one second region of dielectric-material-capped graphene layer structure by removing substantially all resist material;
• and
• (X) forming a second layer of dielectric material on and across the at least one second region of dielectric-material-capped graphene layer structure, the ohmic contacts and at least an adjacent portion of the substrate.

An electronic device precursor comprising:

• a substrate;
• a patterned dielectric-material-capped graphene layer structure comprising a first dielectric material on a graphene layer structure on the substrate;
• ohmic contacts on the substrate, each ohmic contact adjacent an edge of the patterned dielectric-material-capped graphene layer structure;
• and
• a second dielectric material on and across the patterned dielectric-material-capped graphene layer structure, the ohmic contacts, and at least an adjacent portion of the substrate;
• wherein the patterned dielectric-material-capped graphene layer structure has an area of 20 mm2 or less.