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Effects of electric field in band alignment measurements using photoelectron spectroscopy
Author(s) -
Chiam S. Y.,
Liu Z. Q.,
Pan J. S.,
Manippady K. K.,
Wong L. M.,
Chim W. K.
Publication year - 2012
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3851
Subject(s) - x ray photoelectron spectroscopy , heterojunction , electric field , work function , band bending , computational physics , spectrometer , spectroscopy , spurious relationship , work (physics) , kinetic energy , materials science , chemistry , optoelectronics , optics , physics , computer science , nuclear magnetic resonance , nanotechnology , quantum mechanics , layer (electronics) , machine learning , thermodynamics
Band alignment of most heterojunctions can be accurately measured by photoelectron spectroscopy. However, care must be taken in the measurement and analysis of the data to accurately account for any spurious effects. In this work, we focus on the effects of electric field in both core‐levels and work function measurements. We measured experimentally the relaxation energies of remote screening and examine the resultant potential drop. We will then introduce a model to show the extent of errors that are possible in core‐level measurements with this potential difference across the thin film. This model can be effectively used to model any field effects like differential charging or band bending in heterojunction measurements. Both the experimental and simulation results showed that film thickness of greater than 4 nm are relatively free of remote screening effects from the substrate. Finally, we will show that measuring the low kinetic energy electrons requires a more negative applied bias over that necessary to overcome the spectrometer work function. Copyright © 2011 John Wiley & Sons, Ltd.