The scientists used a technique called alloying. To do this, you need to implant the atoms of the elements of one device, under the surface of the original gadget. The implanted atoms alter the electrical properties of the uppermost layer without harming it and create a unique label that can be read with an electronic scanner.
This method can be called an electronic sticker: it is unique and there are no two similar ones.
To create an electronic identifier, the scientists applied a 10-nanometer film of doped aluminum onto silicon wafers with an area of about 10 cm². They have then broken into pieces the size of a postage stamp so that they could fit into an atomic force microscope (AFM). The team then used an AFM needle tip to push aluminum atoms a few nanometers into the silicon. The diameter of the implanted areas was tiny, no more than 200 nm.
Now, this tag can be built into the device during the production process, and the user can easily check whether he has an original gadget or not.
The new development will help improve the supply chain of original gadgets and reduce the black market.