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Investigating the electrical properties of Si donors in Al x Ga 1– x N alloys
Author(s) -
James G. R.,
Omnès F.,
Leitch A. W. R.
Publication year - 2006
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200565461
Subject(s) - activation energy , photoconductivity , electrical resistivity and conductivity , analytical chemistry (journal) , shallow donor , doping , electron mobility , hall effect , materials science , chemical vapor deposition , chemistry , optoelectronics , chromatography , electrical engineering , engineering
In this paper a study of the electrical properties of Si‐doped Al x Ga 1– x N is presented. The Al x Ga 1– x N layers, grown using the metalorganic chemical vapour deposition technique, were studied using variable temperature Hall effect and persistent photoconductivity measurements. High quality conducting Al x Ga 1– x N layers were obtained for 0 ≤ x ≤ 0.5, with the mobility decreasing from 215 cm 2 /V s (GaN) to 10 cm 2 /V s (Al 0.51 Ga 0.49 N), at 300 K. The carrier concentration of these layers was typically between 2.5 × 10 18 cm –3 and 7 × 10 17 cm –3 at 300 K. For Al x Ga 1– x N layers with 0 ≤ x ≤ 0.41 the temperature dependence of the carrier concentration between 300 and 15 K could be studied, yielding the Si donor activation energy. The carrier concentrations of higher Al content samples (0.5 ≤ x ≤ 0.65) could not be accurately measured below 300 K, and thus the Si activation energy was obtained from the temperature dependence of the resistivity. It was found that the Si activation energy escalated with increasing Al content of the layers, and followed the trend predicted for a shallow hydrogen‐like donor, up to x = 0.65. Illumination of the samples at low temperature with a blue LED showed that the layers exhibit little persistent photoconductivity, further confirmation that Si remains a shallow donor in Al x Ga 1– x N. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)