Abstract: The invention provides a process for manufacturing a field-effect transistor on a p-type diamond substrate. The process includes depositing a layer of p' doped amorphous silicon or germanium on the surface of the substrate and depositing a layer of a first metal over the p.sup.+ layer. Portions of the layer of the first metal and the p+ layer are selectively removed to define source and drain regions of the transistor. A gate region is defined by an exposed portion of the substrate between the source and drain regions. A layer of a wide-bandgap insulating material is deposited over the source, gate and drain regions and then selectively removed to allow metallic contacts to be applied to the source, gate and drain regions.

Abstract: A composite radiation detection and indicating device comprises first, third and fifth layers of a transparent conductive material, a second layer of semiconductive diamond between the first and third layers, and a fourth layer of liquid crystal material between the third and fifth layers. The layers are sandwiched together so that a diodic structure having a radiation-dependent charge storage characteristic is defined by the first, second and third layers, and a liquid crystal display element is defined by the third, fourth and fifth layers. The invention extends to a radiation detector including the composite device, together with an oscillator for applying a charge to the diodic structure, and a sensor for monitoring the decay of the stored charge. A voltage is applied to the liquid crystal display element to cause it to change state when the charge stored by the diodic structure decays below a predetermined limit.

Abstract: Crystalline diamond is grown on a substrate by placing the substrate on a nitride surface which completely covers a graphite support, creating an atmosphere of a gaseous carbon compound around the substrate, bringing the temperature of the nitride surface and the substrate to at least 600.degree. C., and subjecting the gaseous carbon compound to microwave energy suitable to cause the compound to decompose and produce carbon which deposits on the substrate and forms crystalline diamond thereon.

Abstract: An electronic probe consists of a steel elongate base (10) having a conical tip (12) and a thin layer (14) of semi-conducting diamond of the tip (12). The diamond tip (16), viewed end-on, will generally have a radius of less than 3000 angstroms.