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Citation 31

Accession Number

005078903

Author

Cai YQ. Storer P. Kheifets AS. McCarthy IE. Weigold E.

Institution

Electron. Structure of Mater. Centre, Flinders Univ. of South Australia,
Adelaide, SA, Australia.

Title

Energy-resolved momentum density of amorphous germanium and the effect of
hydrogen adsorption by (e,2e) spectroscopy.

Source

Surface Science, vol.334, no.1-3, 10 July 1995, pp.276-88. Netherlands.

Country of Publication

Netherlands.

Abstract

The energy-resolved momentum density rho ( in ,q) of evaporated amorphous germanium has been studied using a surface-sensitive solid state (e,2e) spectrometer with estimated energy and momentum resolutions of about 2.0 eV and 0.15 a.u., respectively, and has been compared with a LMTO (linear muffin-tin orbitals) calculation for crystalline germanium. The density consists of two main features: one disperses upwards from around -13 eV at zero momentum to around -6 eV at a momentum value of 0.85 a.u., the other appears throughout the momentum values investigated (0 to 16 a.u.) and is confined within 7 eV below the valence band maximum. The former is identified as being due to the lower valence band of the germanium and agrees well with the LMTO calculation both in dispersion and in intensity, whereas only part of the intensity of the latter feature can be attributed to the upper valence bands. Hydrogen adsorption on the germanium surface reduces the intensity of the upper feature, most noticeably at momenta from 0.65 to 0.85 a.u., and introduces features around energies of -7 to -13 eV between momenta of 0.15 and 0.85 a.u. On this basis, contributions to the momentum density from the dangling bonds on the surface and those due to hydrogen adsorption are estimated. These results are discussed in association with early photoemission studies of the same material. (21 References).

Abstract Number

A9522-7920K-004

Subject Headings

Adsorption
Amorphous semiconductors
Dangling bonds
Electron spectra
Elemental semiconductors
Germanium
Hydrogen
Muffin-tin potential
Orbital calculations
Surface states
Valence bands

Key Phrase Identifiers

(e2e) spectroscopy; LMTO calculation; semiconductor; surface-sensitive solid
state spectrometer; linear muffin-tin orbital calculation; crystalline Ge;
energy-resolved momentum density; lower valence band; dispersion; intensity;
upper valence bands; dangling bonds; photoemission studies; 2 to -13 eV; H
adsorption; evaporated amorphous Ge.

Classification Codes

Other electron-surface impact phenomena [A7920K]; Surface states, band
structure, electron density of states [A7320A]; Evaporation and condensation;
interface adsorption and desorption kinetics [A6845D].

Treatment

Experimental.

Chemicals

H/ads; H/el; Ge/sur; Ge/el.

Numeric Data

Electron volt energy -1.3E+01 to 2.0E+00 eV

CODEN

SUSCAS

Language

English.

ISSN

0039-6028.

U.S. Copyright Clearance Center Code

0039-6028/95/$09.50.

Publication Type

Journal Paper.

Update Code

199500.

Copyright

Copyright 1995, IEE.

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