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Effect of Annealing on Defects in As‐Grown and γ‐Ray Irradiated n‐GaN Layers
Author(s) -
Shmidt N.M.,
Davydov D.V.,
Emtsev V.V.,
Krestnikov I.L.,
Lebedev A.A.,
Lundin W.V.,
Poloskin D.S.,
Sakharov A.V.,
Usikov A.S.,
Osinsky A.V.
Publication year - 1999
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/(sici)1521-3951(199911)216:1<533::aid-pssb533>3.0.co;2-s
Subject(s) - irradiation , annealing (glass) , materials science , sapphire , doping , metalorganic vapour phase epitaxy , analytical chemistry (journal) , electron beam processing , optoelectronics , epitaxy , nanotechnology , optics , chemistry , metallurgy , laser , physics , nuclear physics , layer (electronics) , chromatography
γ‐irradiation induced defects ( 60 Co, dose of 3 × 10 19 cm —2 ) in n‐GaN epilayers with a carrier concentration of 10 17 cm —3 (slightly doped) and 10 18 cm —3 (heavily doped) grown by low‐pressure MOCVD on (0001) sapphire substrates have been investigated. The γ‐irradiation decreases the electron concentration ( n ) for the slightly doped epilayers, while it increases that for the heavily doped epilayers. At the same time, the γ‐irradiation causes a decrease in the electron mobility ( μ ) for all epilayers. For heavily doped epilayers, the concentration increase continues during annealing at temperatures up to 250 °C and it has been associated with the activation of neutral complexes. Two electron traps with E = 0.155 eV and 0.95 eV appeared in the γ‐irradiated slightly doped epilayers. The values of n and μ have restored their original values, which have been measured in the as‐grown epilayers, after annealing at 550 °C.