Publication

Valence-Band States of Ion-Bombarded Polystyrene

Giorgio Margaritondo
1991
Journal Articles

Abstract

Ion-bombarded polystyrene with a 0.5-keV Ar+ beam has been investigated by means of photoelectron spectroscopy performed with synchrotron radiation. After a dose of 10(15) ions/cm2 the evolution of the valence band of the bombarded sample towards an amorphous carbonlike configuration is reported. From the analysis of valence-band spectra we estimated the out-diffusion of hydrogen and showed that its electronic states remain well identified and stable until the hydrogen presence is about 35% with respect to the pristine sample. Finally, comparison with mass spectroscopy measurements on deuterated polystyrene has been performed to determine hydrogen evolution during the ion irradiation.

Official source

https://infoscience.epfl.ch/entities/publication/fb44421f-9a22-46b3-a484-f20206dc3d4b

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Giorgio Margaritondo
1991
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/fb44421f-9a22-46b3-a484-f20206dc3d4b

About this result

Related concepts (32)

Hydrogen

Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds.

Valence and conduction bands

In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. In nonmetals, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the conduction band is the lowest range of vacant electronic states. On a graph of the electronic band structure of a semiconducting material, the valence band is located below the Fermi level, while the conduction band is located above it.

Electronic band structure

In solid-state physics, the electronic band structure (or simply band structure) of a solid describes the range of energy levels that electrons may have within it, as well as the ranges of energy that they may not have (called band gaps or forbidden bands). Band theory derives these bands and band gaps by examining the allowed quantum mechanical wave functions for an electron in a large, periodic lattice of atoms or molecules.

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Valence-Band States of Ion-Bombarded Polystyrene

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