Zinc oxide is a wide band gap piezoelectric semiconductor.1 In addition, it is one of the few compounds predicted to have a ferromagnetic transition temperature that exceeds 300 K when doped with magnetic elements.2 We have constructed a nanowire growth system to allow studies of carrier mediated magnetism in magnetically doped wide band gap semiconductors. Small diameter nanowires offer a distinct advantage over their bulk counterparts: if the nanowire diameter is smaller than the carrier screening length it may be possible to gate electrical carriers throughout the entire volume of the nanowire, allowing electrical control of the ferromagnetic transition temperature. Transport measurements may clarify previous claims of magnetism in ZnO that were solely supported by magnetometry measurements. In addition, efficient electrical gating may allow the transition temperature to be tuned over a wider range than has been demonstrated with GaMnAs films.3
References
1. F. S. Galasso, Structure and properties of inorganic solids (Pergamon Press, New York, 1970).
2. T. Dietl et al., Science 287, 1019 (2000).
3. D. Chiba et al., Science 301, 943 (2003).
References
1. F. S. Galasso, Structure and properties of inorganic solids (Pergamon Press, New York, 1970).
2. T. Dietl et al., Science 287, 1019 (2000).
3. D. Chiba et al., Science 301, 943 (2003).
SEM image showing growth of ZnO nanowires from a Si substrate. The nanowires were grown in the Petta lab by Ted Gudmundsen.