Electrochemical Lift-Off Cell for Producing Diamond Membranes

Designed by Dr Joshua Tully for work in the Macpherson Group at the University of Warwick.

Details:

This electrochemical cell is designed to enable the electrochemical etching of the graphite layer in implanted diamond samples. Etching this graphitic layer frees the diamond cap layer above the implant, giving a thin diamond membrane which would be difficult to produce by other means.

This can be used to produce intrinsic diamond membranes for quantum optical applications, see Tully et. al. Carbon. 2021. 

Printing:

The cell should be printed in a resin which is chemically compatible with the etch solution you plan to use. If you are etching an intrinsic diamond sample, it is advantageous to print the cell in a clear resin, so that the progress of the etch can be monitored.

The gasket can be printed from an “elastic” type resin, or cut from silicone, either by hand or using a CNC cutting machine like a Cricut.

Assembly and Use:

After printing, one side of the “Etch_Cell_Inverted_Top” part should be polished to optical transparency, to allow in-situ monitoring of the etch progress. Two platinum wires, 15 mm long and 0.75 mm in diameter should be soldered to wires, and then pushed through the holes in the “Etch_Cell_Inverted_Base” part from the bottom. The platinum electrodes can then be sealed into the cell using a two part epoxy.

The sample to be etched should be glued to the center of a 10x3 mm piece of poly-carbonate with superglue. The cell can be assembled using M3 hardware on the outside, with M3 nylon screws used to retain the sample inside the cell.

The solution can then be pumped round the cell at ~250 ml/min (ideally with a peristaltic pump), and 30V applied between the platinum electrodes.