Acceptor ionization energies in gallium nitride: chemical trends and electronegativities

The chemical trends of the acceptor ionization energies of column II acceptors in GaN, a wide-bandgap semiconductor recently in the forefront of research, are examined. Consideration of the electronegativity differences between the acceptor atoms and the host atom they substitute allows us to establish a correlation between the acceptor ionization energies and the chemical nature of the acceptor atoms, similar to the already known cases of GaAs and GaP. Based on this, the effective mass acceptor ionization energy in GaN is estimated to be 85 ± 8 meV, about half of the value recently proposed in the literature.