Few-layer Graphene Recipe - Christo Smallwood Part II Thesis

  • 0.1 mm thick copper substrate. Be careful to maintain surface smoothness and avoiding creasing.
  • ~ 1cm2 sized pieces are cut, and then cleaned in acetone followed by IPA and DI water. Rinses are 10 minutes each by sonication.
  • Samples loaded onto a vacuum boat and sealed in the CVD tube. The CVD is pumped down to vacuum.
  • The CVD is backfilled with argon gas up to atmospheric pressure, before opening the release valve to the exhaust to allow a continued flow of gas. Methane and hydrogen lines are run for ~5 minutes to ensure they are clear.
  • CVD furnace ramped to 1000C and gas flow set to 200 sccm Ar and 100 sccm H2/Ar mix before sliding the sample into the hot zone.
  • Anneal for 60 minutes. Improved graphene electrical quality is possible for longer anneals at 1050C.
  • Reduce H2/Ar mix gas line flow to 30 sccm, maintain Ar line at 200 sccm and turn on the 1% CH4/Ar mix line at 10 sccm. Leave for 1 hour at 1000C.
  • Turn off the CH4/Ar mix line and slide the sample from the hot zone to outside the furnace for rapid cooling. Unseal the CVD tube only when the sample is cooled to prevent copper oxidation.

Large-area Single Crystal Monolayer Graphene - Ye Fan and Yimin Wu Large Single Crystals of Graphene on Melted Copper Using Chemical Vapor Deposition

  • Cut Cu and W into 1cm*1cm pieces. Flaten the metal pieces with cotton tips and sonicate them subsequently in acetone, HCl (37%HCL:H20 = 1:3), DI water, and IPA for 5 minutes in each step.
  • Blow dry and load samples into the quartz tube.
  • (ALTERNATIVE: Pump down the CVD) and flush the system with 200 sccm Ar, 100 sccm H2 and 100 sccm 1% CH4 for 10 minutes.
  • Turn on the furnace and increase the temperature to 1060C with the flow of 200 sccm Ar and 100 scccm H2.
  • Further increase the temperature to 1090C whiel keep teh same flow rate of gas. Anneal the sample for another 30 minutes.
  • // Reduce the H2 flow to 80 sccm and turn on the 1% CH4 at 10 sccm for 90 minutes for continuous graphene growth.
  • Turn off methane flow and the furnace. Slowly move sample out of the heating zone.