Greg,

You can use either a carbon paint or silver paint (dag) to do just what
you want.  They are both soluble in acetone.  SPI supplies this product.
Here is there web site http://www.2spi.com/.

Best regards,

Jon Hiller

Jon M. Hiller
Electron Microscopy Center
Argonne National Laboratory
9700 South Cass Avenue
Argonne, IL.  60439
Tel:  630-252-9558
Fax:  630-252-4289