Doping and defect control of ferromagnetic semiconductors formed by ion implantation and pulsed-laser melting

✍ Scribed by O.D. Dubon; M.A. Scarpulla; R. Farshchi; K.M. Yu

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 156 KB
• Volume: 376-377
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.12.159

✦ Synopsis

We demonstrate a simple but effective route for the synthesis of ferromagnetic semiconductors that combines Mn ion implantation (II) and pulsed-laser melting (PLM). By this process Ga 1Àx Mn x As films exhibiting a ferromagnetic Curie temperature (T C ) exceeding 130 K have been synthesized. These materials possess electrical and magnetic characteristics similar to molecular beam epitaxy-grown (MBEgrown) films that are tunable through experimental parameters such as implantation dose, laser energy fluence, and co-doping with Te donors. We have also used II-PLM to form ferromagnetic single-crystalline Ga 1Àx Mn x P films. These films display magnetic properties similar to their arsenide counterparts despite remaining non-metallic and becoming strongly insulating at low temperatures. Unlike asgrown MBE films, both Ga 1Àx Mn x P and Ga 1Àx Mn x As formed by II-PLM do not contain Mn at interstitial sites; instead, nonsubstitutional Mn atoms are found to be randomly located, perhaps as clusters. As a result, post-PLM thermal annealing at temperatures higher than 300 1C leads to a decrease in T C as Mn atoms leave substitutional sites.