Methods for fabricating graphene device topography and devices formed therefrom

Abstract

Methods for forming graphite-based structures ( 302, 304 ), in which a substrate is patterned to form a plurality of elements ( 104, 208 ) on the substrate ( 102 ), are provided. A trench separates a first element from an adjacent element in the plurality. The surface of the first element and the surface of the trench (i) are respectively characterized by different first and second elevations and (ii) are separated by a side wall of the first element. Orthogonal projections of the surface of the first element and the surface of the trench onto a common plane are contiguous or overlapping. In the method, a first graphene layer ( 302 ) on the entire first surface and a second graphene layer ( 304 ) on the entire second surface are concurrently generated. The second graphene layer has a thickness that is less than a difference between the first and second elevations. Thus, a graphite-based structure having isolated first and second graphene layers is formed. The first and second graphene layers may be doped to the same or to the opposite conductivity type and may also comprise pn junctions.

1 - 86 . (canceled) 
     
     
         87 . A method for forming a graphite-based structure on a substrate comprising:
 (A) patterning the substrate to form a plurality of elements on the substrate, where a first element in the plurality of elements is separated from an adjacent element on the substrate by a corresponding trench in a plurality of trenches in the substrate, wherein
 (i) the first element in the plurality of elements has a first surface, 
 (ii) a first trench in the plurality of trenches separates the first element from the adjacent element in the plurality of elements, the first trench having a second surface, 
 (iii) the first surface and the second surface are separated by a first side wall of the first element, 
 (iv) the first surface is characterized by a first elevation, 
 (v) the second surface is characterized by a second elevation, 
 (vi) the first elevation is other than the second elevation, and 
 (vii) a first orthogonal projection of the first surface and a second orthogonal projection of the second surface on a common plane are contiguous or overlapping, and 
   (B) generating a first graphene layer on the entire first surface and a second graphene layer on the entire second surface, wherein the second graphene layer has a thickness that is less than a difference in the first elevation and the second elevation, thereby creating the graphite-based structure in which the second graphene layer is isolated from the first graphene layer, wherein the first graphene layer comprises one or more graphene sheets and wherein the second graphene layer comprises one or more graphene sheets.   
     
     
         88 . The method of  claim 87 , wherein the substrate comprises silicon (Si), silicon carbide (SiC), germanium (Ge), boron nitride (BN), molybdenum sulfide (MoS), copper (Cu), nickel (Ni), platinum (Pt), gold (Au), cobalt (Co), ruthenium (Ru), palladium (Pd), titanium (Ti), silver (Ag), aluminum (Al), cadmium (Cd), or iridium (Ir), silicon dioxide (SiO 2 ) glass, or soda lime glass formed from silicon dioxide. 
     
     
         89 . The method of  claim 87 , wherein the substrate comprises silicon dioxide glass doped with boron (B), barium (Ba), thorium oxide (ThO 2 ), lanthanum oxide (La 2 O 3 ), iron (Fe) or cerium(IV) oxide (CeO 2 ). 
     
     
         90 . The method of  claim 87 , wherein the substrate comprises aluminosilicate, borosilicate, dichroic, germanium/semiconductor, glass ceramic, silicate/fused silica, soda lime, quartz, chalcogenide/sulphide, or cereated glass. 
     
     
         91 . The method of  claim 87 , further comprising:
 (C) selectively doping the substrate with carbon, subsequent to the patterning (A) but prior to the generating (B), to produce a first carbide layer within the first surface of the substrate or a second carbide layer within the second surface of the substrate.   
     
     
         92 . The method of  claim 91 , wherein
 the first carbide layer has a depth that is between 1 nm and 2 nm, and   the second carbide layer has a depth that is between 1 nm and 2 nm.   
     
     
         93 . The method of  claim 91 , wherein
 the first carbide layer has a depth that is between 100 nm and 1 μm, and   the second carbide layer has a depth that is between 100 nm and 1 μm.   
     
     
         94 . The method of  claim 91 , wherein
 the first carbide layer has a depth that is between 1 μm and 5 μm , and   the second carbide layer has a depth that is between 1 μm and 5 μm.   
     
     
         95 . The method of  claim 87 , further comprising:
 (C) selectively doping the substrate with a first dopant, thereby producing the first graphene layer or the second graphene layer with a first charge carrier, wherein
 the doping the substrate with the first dopant is conducted either (i) prior to or (ii) subsequently to the generating (B) when the substrate comprises the semiconducting material, and 
 the doping the substrate with the first dopant is conducted subsequent to the generating (B) when the substrate comprises the dielectric material or the metallic material. 
   
     
     
         96 . The method of  claim 95 , wherein the first dopant comprises phosphorous, arsenic, selenium, tellurium, silicon, germanium, boron, aluminium, beryllium, zinc, antimony, or carbon. 
     
     
         97 . The method of  claim 95 , wherein the first carrier is electrons or holes. 
     
     
         98 . The method of  claim 95 , further comprising:
 (D) selectively doping the substrate with a second dopant, thereby producing the first graphene layer or the second graphene layer with a second charge carrier, wherein
 the doping the substrate with the second dopant is conducted prior to or subsequent to the generating (B) when the substrate comprises the semiconducting material, and 
 the doping the substrate with the second dopant is conducted subsequent to the generating (B) when the substrate comprises the dielectric material or the metallic material, 
 the second dopant is different than the first dopant, and 
 the second charge carrier has a charge opposite to the first charge carrier. 
   
     
     
         99 . The method of  claim 98 , wherein the second dopant comprises phosphorous, arsenic, selenium, tellurium, silicon, germanium, boron, aluminum, beryllium, zinc, antimony, or carbon. 
     
     
         100 . The method of  claim 87 , wherein the patterning the substrate to form the plurality of elements comprises a combination of etching the first trench in the substrate and depositing the first element adjacent to the first trench. 
     
     
         101 . The method of  claim 100 , wherein the etching the first trench in the substrate comprises photolithography, X-ray lithography, reactive ion etching, plasma etching, sputter etching, e-beam direct writing, or a combination thereof. 
     
     
         102 . The method of  claim 100  wherein the depositing the first element on the substrate is performed by sputtering deposition of carbide or carbon. 
     
     
         103 . The method of  claim 102 , wherein the depositing the first element on the substrate further comprises:
 sputtering a metallic catalyst on the substrate prior to sputtering deposition of carbide or carbon, thereby promoting subsequent growth of the first graphene layer or the second graphene layer, wherein the metallic catalyst comprises platinum (Pt), gold (Au), cobalt (Co), ruthenium (Ru), palladium (Pd), titanium (Ti), silver (Ag), aluminum (Al), cadmium (Cd), or iridium (Ir).   
     
     
         104 . The method of  claim 87 , wherein the first surface of the first element is substantially horizontal, has a slope or an arcuate property, and wherein the first surface of the first element has an average elevation that is the first elevation. 
     
     
         105 . The method of  claim 87 , wherein the first surface of the first element is substantially flat or has an arcuate property. 
     
     
         106 . The method of  claim 87 , wherein the second surface of the first trench is substantially horizontal, has a slope or is bent, and wherein the second surface of the second element has an average elevation that is the second elevation