Dilute magnetic semiconductors (DMSs) are semiconductors doped with transition metal atoms. The dilute magnetic semiconductors are of the spintronic devices which could combine the data storage, detection, logical and communication capabilities on a single chip. Dilute magnetic semiconductors devices have been started with II-IV compound semiconductors but these materials became less attractive for further development due to the difficulty in doping of magnetic elements. The III-IV compound semiconductors are promising materials for spintronic applications because of its Curie temperature higher than room temperature. The III - V semiconductor (GaN and GaSb) based dilute magnetic semiconductor devices have great advantages such as high speed and low power electronic devices due to its spin direction and spin coupling. DMSs are synthesised using ion implantation technique found to be prominent due to non equilibrium and solubility limit of magnetic elements. Synthesis, magnetic interaction, mechanism of ferromagnetism in DMSs with the help of various related characterization results are given in this book.