Defects in AlN: High-frequency EPR and ENDOR studies

✍ Scribed by Sergei B. Orlinskii; Pavel G. Baranov; Anna P. Bundakova; Matthias Bickermann; Jan Schmidt

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 291 KB
• Volume: 404
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2009.08.239

✦ Synopsis

Compensation by deep-level defects and self-compensation of shallow donors in AlN are discussed in the light of results of a high-frequency pulse electron paramagnetic resonance (EPR) and electronnuclear double resonance (ENDOR) study. It was suggested on the basis of the large mostly isotropic hyperfine interaction with A( 27 Al) ¼ 406 MHz that one of the deep-level defect is isolated interstitial Al 2+ atom. Two types of effective-mass-like shallow donors with a delocalised wave function were shown to exist in unintentionally doped AlN. The experiments demonstrate how the transformation from a shallow donor to a deep (DX) centre takes place and how the deep DX centre can be reconverted into a shallow donor forming a spin triplet and singlet states with an exchange interaction of about 24 cm À1 and with a lowest triplet state.