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Hydrogen diffusion is investigated in boron-doped diamond from the redistribution profiles under thermal annealing of an initial step-like profile of (B,H) pairs located in a shallow region below the surface. For boron concentrations in the range 2×1019–1×1020 cm−3, the profiles are Gaussian-like and effective diffusion coefficients can be calculated. From the diffusion activation energy, we deduce a (B,H) pair dissociation energy of 2.5 eV. For lower boron concentrations, the redistribution of hydrogen is inhibited by the presence of deep traps for hydrogen which might be associated with structural defects. [Copyright &y& Elsevier]

Hydrogen diffusion studies were performed in GaN samples with different Fermi level positions. It is shown that, at 350 °C, hydrogen diffusion is quite fast in heavily Mg doped p-type material with the Fermi level close to E[sub v]+0.15 eV, considerably slower in high-resistivity p-GaN(Zn) with the Fermi level E[sub v]+0.9 eV, while for conducting and semi-insulating n-GaN samples with the Fermi level in the upper half of the band gap no measurable hydrogen diffusion could be detected. For these latter samples it is shown that higher diffusion temperature of 500 °C and longer times (50 h) are necessary to incorporate hydrogen to appreciable depth. These findings are in line with previously published theoretical predictions of the dependence of hydrogen interstitials formation in GaN on the Fermi level position. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]