PubMed Health⌕ Search

Biomedical subjects

A Zunger

Publications and source records attributed to A Zunger.

At least 19 recordsLinked to original sources
PubMed2000

Indium-indium pair correlation and surface segregation in InGaAs alloys

In-In pair correlations and In surface segregation in In xGa 1-xAs alloys are studied by first-principles total-energy calculations. By calculating the substitution energy of a single In atom, we find that the near-surface energetics explains the observed In segregation on InGaAs(001)-beta2(2x4) surfaces. Indium surface segregation further enhances the In site selectivity, thus the long-range ordering. We find that the [110] and [001] In-In pair correlations are repulsive and nearly isotropic in bulk but are highly anisotropic near the (001) surface. The sign of the [110] In-In interaction energies vs the distance from the surface is oscillatory. These findings explain the recent puzzling cross-sectional x-STM results.

Journal Article↗
PubMed2000

Microscopic origin of the phenomenological equilibrium "Doping limit Rule" in n-type III-V semiconductors

The highest equilibrium free-carrier doping concentration possible in a given material is limited by the "pinning energy" which shows a remarkable universal alignment in each class of semiconductors. Our first-principles total energy calculations reveal that equilibrium n-type doping is ultimately limited by the spontaneous formation of close-shell acceptor defects: the (3-)-charged cation vacancy in AlN, GaN, InP, and GaAs and the (1-)-charged DX center in AlAs, AlP, and GaP. This explains the alignment of the pinning energies and predicts the maximum equilibrium doping levels in different materials.

Journal Article↗