A method for forming on a substrate an electronic device including an electrically conductive or semiconductive material in a plurality of regions, the operation of the device utilising current flow from a first region to a second region, the method comprising: forming a mixture by mixing the material with a liquid; forming on the substrate a confinement structure including a first zone in a first area of the substrate and a second zone in a second area of the substrate, the first zone having a greater repellence for the mixture than the second zone, and a third zone in a third area of the substrate spaced from the second area by the first area, the first zone having a greater repellence for the mixture than the third zone, and depositing the material on the substrate by applying the mixture over the substrate whereby the deposited material may be confined by the relative repellence of the first zone to spaced apart regions defining the said first and second regions of the device and being electrically separated in their plane by means of the relative repellence of the first zone and to be absent from the first area of the substrate so as to resist the flow across the first zone of electrical current between the spaced apart regions of the deposited material. |