In:
MRS Proceedings, Springer Science and Business Media LLC, Vol. 482 ( 1997)
Kurzfassung:
The effect of p- and n-type doping (using Mg and Si, respectively) in the microstructure of GaN, grown epitaxially on (0001)Al 2 O 3 and (111)Si, is studied with X-ray absorption measurements at the N-K-edge. A distortion in the local microstructure around the N atom is detected in the undoped and the Mg doped samples. The N atom is 4-fold coordinated with n Ga atoms in the expected distance and 4-n atoms at a distance longer by 0.28Å, where 2.9 〈 n 〈 3.3. Such a distortion, which is attributed to the inward relaxation and the strong interaction between the Ga atoms surrounding the nitrogen vacancies (VN), does not exist in the Si doped sample (carrier concentration=1.57×10 18 cm −3 ) where the formation of V N is suppressed due to the n-type doping. However, in GaN:Si the N atom is undercoordinated with 3.3 nearest neighbors instead of 4. This undercoordination indicates the presence of V Ga and/or N Ga antisite defects. Finally, from the nearest neigbohr distances the lattice parameters were calculated and it is found that although the a and c vary by about 1.5%, the ratio of the lattice constants, c/a, remains constant and equal to 1.63.
Materialart:
Online-Ressource
ISSN:
0272-9172
,
1946-4274
DOI:
10.1557/PROC-482-381
Sprache:
Englisch
Verlag:
Springer Science and Business Media LLC
Publikationsdatum:
1997
