Activation energies of Si donors in GaN

Autor: W. Götz, C. P. Kuo, C. Chen, W. Imler, N. M. Johnson, H. Liu
Rok vydání: 1996
Předmět:
Zdroj: Applied Physics Letters. 68:3144-3146
ISSN: 1077-3118
0003-6951
DOI: 10.1063/1.115805
Popis: The electronic properties of Si donors in heteroepitaxial layers of GaN were investigated. The n‐type GaN layers were grown by metalorganic chemical vapor deposition and either intentionally doped with Si or unintentionally doped. The samples were evaluated by variable temperature Hall effect measurements and photoluminescence (PL) spectroscopy. For both types of samples the n‐type conductivity was found to be dominated by a donor with an activation energy between 12 and 17 meV. This donor is attributed to Si atoms substituting for Ga in the GaN lattice (SiGa). The range of activation energies is due to different levels of donor concentrations and acceptor compensation in our samples. The assignment of a PL signature to a donor–acceptor pair recombination involving the Si donor level as the initial state of the radiative transition yields the position of the optical Si donor level in the GaN bandgap at ∼Ec–(22±4) meV. A deeper donor level is also present in our GaN material with an activation energy of ∼3...
Databáze: OpenAIRE