Good electrical conductors are metals. An easily accessible explanation can be made easier by the classical view Consummation of the metal binding. The atoms will be through a gas of almost free moving valence electrons are held together. These electrons can therefore without great expenditure of energy in any direction through the crystal solid moves.
The resistance in a metal increases with temperature, which increased by more disturbing influence of vibrating lattice atoms can be explained. In semiconductor devices are used for contacting and for traces of course, metals are used. In some cases, the expensive gold and silver materials used, with the best leadership qualities. Frequently, however, the use of aluminum and copper.