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Optical Spectroscopy of Mg‐ and C‐Related Donor and Acceptor Levels in GaN Grown by MBE
Author(s) -
Strauf S.,
Michler P.,
Gutowski J.,
Birkle U.,
Fehrer M.,
Einfeldt S.,
Hommel D.
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<557::aid-pssb557>3.0.co;2-4
Subject(s) - molecular beam epitaxy , photoluminescence , exciton , doping , acceptor , materials science , dopant , shallow donor , spectroscopy , optoelectronics , binding energy , analytical chemistry (journal) , chemistry , epitaxy , condensed matter physics , nanotechnology , atomic physics , physics , layer (electronics) , quantum mechanics , chromatography
We present photoreflectance (PR) in combination with temperature and density dependent photoluminescence (PL) on undoped as well as on Mg‐ and C‐doped GaN grown by molecular beam epitaxy (MBE). We determined the binding energy of the free A‐exciton, the residual donor‐bound exciton and the Mg‐acceptor‐bound exciton to (26 ± 1), (5 ± 1) and (18 ± 1) meV, respectively. In n‐type GaN a residual DAP band appears independent of the particular type of dopant. Free‐hole concentrations up to 10 18 cm —3 in MBE grown p‐GaN:Mg were achieved without generation of deep compensating donors. Moreover, we found evidence for a second DAP series involving a shallow compensating donor level built in along with Mg doping. The correlation of different DAP bands to the respective type of conductivity opens an alternative way to control the p‐type doping in GaN:Mg without the need for electrical contacting.