Theory of hydrogen in diamond

Abstract

Hydrogen is a ubiquitous impurity in diamond but in contrast to other group IV materials the microscopic structure adopted in bulk material has largely remained elusive. It has therefore been the role of modelling to predict the properties of H in bulk diamond, as well as the interactions with impurities and other defects. Presented here is an account of the current theoretical understanding of hydrogen in diamond. Contents1. Introduction 552 2. Theoretical approaches 554 2.1. Hartree-Fock based methods 554 2.2. Density functional methods 555 2.3. Tight-binding approaches 555 2.4. Basis sets and Brillouin zone sampling 556 2.5. Classical versus quantum mechanical treatment of the H atoms 556 2.6. Summary 556 2.7. Calculation of experimental observables 557 3. Muonium and interstitial hydrogen 561 3.1. Muonium hyperfine coupling constants 563 3.2. Electrical activity of isolated hydrogen 564 3.3. Vibrational modes of interstitial H 565 3.4. Diffusion of interstitial hydrogen 565 3.5. Solubility of bond-centred hydrogen 567 3.6. Hydrogen in near-surface region 567 4. Di-hydrogen aggregates 568 5. Hydrogenated lattice vacancies 569

Oxide muonics: II. Modelling the electrical activity of hydrogen in wide-gap and high-permittivity dielectrics

“…Nonetheless, the disproportionation of hydrogen is otherwise virtually unknown in chemistry, to the extent that the importance-or even the existence-of hydride ions in 10 Negative-U behaviour is likewise calculated for hydrogen in silicon, where the hydride ion occupies a cage-centre site but the proton a bond centre (Van de Walle et al 1989). This contrasts with the case of H in diamond, however, which is calculated to be a strongly positive-U system, albeit with neither the neutral centre nor the negative ion having any 1s character at all (Goss 2003). oxides is a question of some topical interest, not to say contention (see, for example, Poulsen 2001, Steinsvik et al 2001, Norby et al 2004 11 . For the more intuitive case of positive U (figure 2(b)), the charge state which hydrogen adopts depends on the Fermi level as defined by other dopants or redox-active impurities.…”

Importance of Quantum Tunneling in Vacancy-Hydrogen Complexes in Diamond

“…With the development of high-quality single crystal chemical vapor deposition (CVD) diamond, exhibiting properties potentially suitable for semiconductor applications [1], the role of defects in determining electronic and optical properties is becoming increasingly relevant. One element which has become the focus of considerable attention is hydrogen [2], typically present in the CVD growth process, which can be incorporated into the layer. The first step towards understanding and potentially manipulating hydrogen defects is a microscopic model of the hydrogen defects in the lattice.…”

Quantum behaviour of hydrogen and muonium in vacancy-containing complexes in diamond

“…H passivates both donors and acceptors in diamond [16], removing the electronically active levels from the bandgap. Goss [16] gives a review of the theoretical work in this area.…”

“…H passivates both donors and acceptors in diamond [16], removing the electronically active levels from the bandgap. Goss [16] gives a review of the theoretical work in this area. Hydrogen can be hard to detect experimentally, partly because of the strong tendency for interstitial atomic hydrogen to form molecules [17].…”