A pân junction is a boundary or interface between two types of semiconductor materials, p-type and n-type, inside a single crystal of semiconductor. The p side contains an excess of holes, while the n side contains an excess of electrons in the outer shells of the electrically neutral atoms there. This allows electrical current to pass through the junction only in one direction. The p-n junction is created by doping, for example by ion implantation, diffusion of dopants, or by epitaxy ...
ITER is an international collaboration to build the first fusion science experiment capable of producing a self-sustaining fusion reaction, as a way of generating a clean, safe, and sustainable power.
The reactor pictured, ITER, is under construction and is planned to be the first fusion reactor large enough to produce a net gain of energy. Basically, it mashes two isotopes of hydrogen, deuterium and tritium, together at such high energies that they combine into one atom.