Transition metals in ZnGeP2 and other II–IV–V2 compounds

✍ Scribed by W. Gehlhoff; D. Azamat; A. Hoffmann; N. Dietz; O.V. Voevodina

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 239 KB
• Volume: 376-377
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.12.198

✦ Synopsis

Semiconductors that exhibit room-temperature ferromagnetism are central to the development of semiconductor spintronics. Transition metal (TM)-doped A II B IV C V 2 are a promising class of such system. These ternary compound semiconductors have two metal sites A and B that can be substituted by the TMs. A site preference for TM incorporation is crucial for a possible explanation of ferromagnetism since dependent on the TM valent state holes or electrons can be released. For low Fe-and Cr-doped ZnGeP 2 , our EPR investigations revealed in addition to the well-known native defects the presence of substitutional Fe 2+ (3d 6 , S ¼ 2) on Zn site, Fe 3+ (3d 5 , S ¼ 5

2 ) and Cr 4+ (3d 2 , S ¼ 1) on Ge site. A photo-induced recharging of Fe 2+ to Fe + is observed. The Cr 4+ center exhibits a wellresolved phosphorus ligand hyperfine splitting. For Fe 2+ and Fe 3+ , the magnetic site inequivalence of each of the both Zn and Ge sites, respectively, has been detected. Moreover, anti-ferromagnetically coupled Mn 2+ -Mn Zn 2+ pairs have been observed in Mn-doped ZnGeP 2 .