Leonidas Tsetseris

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Hydrogen plays an important role in MOSFETS as it is intentionally introduced to passivate defects (primarily Si dangling bonds) at the Si–SiO2 interface. At the same time, hydrogen has long been known to be involved in many degradation processes, with much attention being devoted recently to bias-temperature instability (BTI). Here, we give an overview of(More)
Transition-metal nitrides (TMN) have exceptional stability, which underlies their use in various applications. Here, we study the role of N point defects on the stability of prototype TMNs using first-principles calculations. We find that distinct regimes for TMN changes relate to specific atomic-scale mechanisms, namely, diffusion of N interstitials(More)
A key element of functionalizing nanocrystals with organic molecules is the nontemplated selective adsorption of different molecules on different facets. Here we report scanning-tunneling-microscopy images of perylene-3,4,9,10-tetracarboxylic-dianhydride and 2,5-dimethyl-N,N'-dicyanoquinonediimine on silver, demonstrating selective adsorption on different(More)
The mechanical elongation of a finite gold nanowire has been studied by molecular dynamics simulations using different semiempirical potentials for transition metals. These potentials have been widely used to study the mechanical properties of finite metal clusters. Combining with density functional theory calculations along several atomic-configuration(More)
Given that H(2)O dissolves minimally in quartz, the mechanism for the ubiquitous dissolution of H(2)O in silica glasses has been a long-standing puzzle. We report first-principles calculations in prototype silica glass networks and identify the ring topologies that allow the exothermic dissolution of H(2)O as geminate Si-O-H groups. The topological(More)
In the quest for the construction of silicene, the silicon analogue of graphene, recent experimental studies have identified a number of distinct ultrathin Si over-layer structures on a Ag(111) surface. Here we use first-principles calculations to probe associated atomic-scale mechanisms that can give rise to this rich behavior of Si wetting layers. We(More)
We used density functional theory calculations to probe the chemical reactivity of graphene and single-wall carbon nanotubes (CNTs) toward the small molecules O(2), H(2), N(2), C(2)H(2), CO, and CO(2). We found that there is a threshold CNT size below which C(2)H(2) and CO, typical feedstock precursors for CNT growth, become trapped in decorated(More)
Recent studies have examined the possibility of growing honeycomb silicene and germanene, the silicon and germanium analogues of graphene. Here we use first-principles calculations to examine the relative stability of a number of other single-layer structures that are derived from prominent surface reconstructions of group-IV semiconductors. We find that Si(More)
Experimental studies have shown that honeycomb silicene layers can grow on various metal substrates. Here we demonstrate using first-principles calculations that hydrogenation and calcium intercalation can be employed to break bonds between a silicene overlayer and a silver surface. The end result of the former process is the creation of a silicane(More)