Ab initio calculations of anharmonicity of the C-H stretch mode in HCN and GaAs

Identification of the structure of the 3107 cm(-1) H-related defect in diamond

A prominent hydrogen-related infrared absorption peak seen in many types of diamonds at 3107 cm(-1) has been the subject of investigation for many years. It is present in natural type-Ia material and can be introduced by heat-treating synthetic or CVD diamond. Based upon the most recent experimental data, it is thought that the defect giving rise to this vibrational mode is vacancy-related and is likely to contain nitrogen. Using first-principles simulations we present a VN3H model for the originating centre that simultaneously satisfies the different experimental observations including the strain response.

First-principles study of the diffusion of hydrogen in ZnO

Zinc oxide, a wide-gap semiconductor, typically exhibits n-type conductivity even when nominally undoped. The nature of the donor is contentious, but hydrogen is a prime candidate. We present ab initio calculations of the migration barrier for H, yielding a barrier of less than approximately 0.5 eV. This indicates isolated hydrogen is mobile at low temperature and that thermally stable H-related donors must logically be trapped at other defects. We argue this is also true for other oxides where H is a shallow donor.

Theory of hydrogen in semiconductors

Hydrogen exhibits several distinct effects in semiconductors. These include: the neutralization of shallow impurities; the removal of deep states which act as re­combination centres; the catalytic enhancement of oxygen diffusion; the change in the electrical characteristics of transition metal impurities. The basic theoretical methods that have been used to investigate these are described along with their principal results and outstanding problems.