Detailed studies of mechanisms for hydrogen dissociative adsorption and diffusion on pure and nitrogen-doped (8, 0) carbon nanotubes are carried out using the first-principles density functional theory method. (1) For pure carbon nanotubes, we have identified the energetically most favorable... (Read more)

In a recent experiment, Derycke et al. have made the exciting observation that H₂ molecules readily adsorb dissociatively on the c(4×2) but not on the 3×2 surface of SiC(001) at room temperature. To unravel this spectacular reactivity difference, we have investigated a... (Read more)

The role of hydrogen in the exfoliation of Ge is studied using cross-sectional transmission electron microscopy, atomic force microscopy, and multiple-internal transmission mode Fourier-transform infrared absorption spectroscopy and compared with the mechanism in silicon. A qualitative model for the... (Read more)

The effects of confining molecular hydrogen within carbon nanohorns are studied via high-resolution quasielastic and inelastic neutron spectroscopies. Both sets of data are remarkably different from those obtained in bulk samples in the liquid and crystalline states. At temperatures where bulk... (Read more)

Ortho-para conversion of isolated interstitial H₂ in single-crystalline Si is studied by Raman scattering. This process is suggested to be caused by the interaction of H₂ with the nuclear magnetic moment of ²⁹Si. At 77 K the ortho-to-para conversion rate is... (Read more)

Hydrogen is released from hydrogenated silicon nitride (SiN_x:H) during thermal treatments. The formation of molecular hydrogen (H₂) in SiN_x:H layers with low mass density is confirmed by Raman spectroscopy. However, no H₂ is observed in... (Read more)

Isolated interstitial H₂ and H₂ bound to interstitial oxygen (O–H₂) in single-crystalline Si are studied by Raman scattering. Two Raman signals at 3199(1) and 3193(1) cm⁻¹ (T0 K) are identified as ro-vibrational transitions of... (Read more)

NaAlH₄ and LiBH₄ are potential candidate materials for mobile hydrogen storage applications, yet they have the drawback of being highly stable and desorbing hydrogen only at elevated temperatures. In this letter, ab initio density functional theory calculations reveal... (Read more)

Negative bias temperature instability has become an important reliability concern for ultra-scaled Silicon IC technology with significant implications for both analog and digital circuit design. In this paper, we construct a comprehensive model for NBTI phenomena within the framework of the standard reaction–diffusion model. We demonstrate how to solve the reaction–diffusion equations in a way that emphasizes the physical aspects of the degradation process and allows easy generalization of the existing work. We also augment this basic reaction–diffusion model by including the temperature and field-dependence of the NBTI phenomena so that reliability projections can be made under arbitrary circuit operating conditions. (Read more)

We present an overview of negative bias temperature instability (NBTI) commonly observed in p-channel metal–oxide–semiconductor field-effect transistors when stressed with negative gate voltages at elevated temperatures. We discuss the results of such stress on device and circuit... (Read more)

The behavior of hydrogen in crystalline silicon is examined with state-of-the-art theoretical techniques, based on the pseudopotential-density-functional method in a supercell geometry. Stable sites, migration paths, and barriers for different charge states are explored and displayed in total-energy... (Read more)