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Characterization of residual transition metal ions in GaN and AlN

Charakterisierung residuärer Übergangsmetallionen in GaN und AlN

Suezawa, M.; Katayama-Yoshida, H.:
ICDS-18 '95. 18th International Conference on Defects in Semiconductors. Part 1. Proceedings
Trans Tech Publications, 1995 (Materials Science Forum 196/201)
International Conference on Defects in Semiconductors <18, 1995, Sendai>
Fraunhofer IAF ()
A1N; Cr; ESR; GaN; photoluminescence; transition metal; Übergangsmetall

In this paper we present photoluminescence (PL), PL excitation and electron paramagnetic resonance (EPR) studies of residual transition metal impurities in a variety of doped and undoped wurtzite GaN epitaxial layers and polycrystailine wurtzite AIN ceramics. For GaN a PL band with a zero-phonon-line (ZPL) at 0.93l eV is frequently observed and is assigned to an intra 3d-shell electronic transition of gallium- substitutional vanadium impurities. Other PL structures with ZPLs at 1.193 and 1.20l eV are observed for GaN and AIN, respectively. An assignment of these luminescences to Ti(2+) or Cr(4+) 3d2-impurities is discussed. Due to Fermi level considerations and due to the fact, that a new Cr(5+) EPR signal from the AlN ceramics seems to be correlated with the 1.20l eV PL, an assignment to Cr(4+) impurities is favored.