There has been a great interest in transition metal (TM) doped diluted magnetic semiconductors
(DMSs) in recent years. This is due to possibility of manipulating their charge and spin degrees of free-
dom. These DMSs are potential candidates for next generation spintronic devices, such as spin-valve
transistors, spin light-emitting diodes, non-volatile storage and logic devices [1–3]. DMSs can be syn-
thesized from wide-band gap semiconductors with the replacement of the host sites of the semicon-
ductors with magnetic impurities [1]. A wide-band gap II–IV and III–V based semiconductors doped
with metal-transition (Fe, Co, and Mn) metals have been studied widely to investigate the room tem-
perature ferromagnetism [2–6]. ZnO was also used as a potential DMSs material, due to its wide band
gap (3.3 eV) and exciton binding energy (60 meV) at room temperature.