Small gap device system and method of fabrication

A thermionic energy converter system, comprising:

• a first electrode comprising a first surface;
• a second electrode comprising a second surface;
• and
• a mesh spacer maintaining a gap between the first and second surfaces;
• wherein:
• the first and second surfaces are arranged facing each other across the gap;
• the mesh spacer electrically and thermally isolates the first electrode from the second electrode;
• the mesh spacer defines a mesh structure comprising a set of vertices and a set of paths connected between vertices of the set, the set of vertices comprising a first, second, and third vertex, the set of paths comprising:
• a first path extending from the third vertex to the second vertex;
• and
• a second path extending from the third vertex to the first vertex;
• the mesh spacer comprises a set of legs extending substantially along the set of paths, the set of legs comprising:
• a first canaliculate leg defining a first lumen extending substantially along the first path;
• and
• a second canaliculate leg defining a second lumen extending substantially along the second path, the second leg connected to the first leg via the set of legs;
• the first lumen defines a first opening facing the first surface;
• the first canaliculate leg comprises a first elongated member, wherein:
• the first elongated member extends substantially along the first path;
• the first elongated member bounds the first lumen, opposing the first opening across the lumen;
• and
• the second surface opposes the first lumen across the first elongated member;
• the mesh spacer defines a plurality of apertures between legs of the set of legs, wherein, for each aperture of the plurality, a respective normal vector from the first surface to the second surface passes through the aperture and does not intersect the mesh spacer;
• the mesh spacer contacts the first surface at a first set of contact points;
• the mesh spacer defines a plurality of protrusions that protrude within the gap toward the second surface, wherein:
• the plurality of protrusions comprises a first protrusion that protrudes from the first elongated member toward the second surface;
• and
• each protrusion of the plurality contacts the second surface;
• and
• for each contact point of the first set, a respective normal vector from the contact point to the second surface does not intersect the plurality of protrusions.