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@INPROCEEDINGS{Schnedler:972158,
author = {Schnedler, Michael and Wang, Yuhan and Lan, Qianqian and
Zheng, Fengshan and Freter, Lars and Lu, Yan and Breuer, Uwe
and Eisele, Holger and Carlin, J. and Butté, J. and
Grandjean, N. and Dunin-Borkowski, Rafal and Ebert, Philipp},
title = {{S}urface {C}alibrated {E}lectron {H}olography: {A}nomalous
{S}train {R}elaxation and {M}inimization of {P}olarization
{C}hanges at {III}-{N}itride {H}etero-{I}nterfaces},
reportid = {FZJ-2023-01102},
year = {2023},
abstract = {Polarization and electron affinity changes at
Al0.06Ga0.94N/GaN and In0.05Ga0.95N/ Al0.06Ga0.94N
interfaces are quantified by off-axis electron holography
(EH) in transmission electron microscopy (TEM), in
conjunction with scanning tunneling microscopy and
spectroscopy, as well as self-consistent simulations of the
electrostatic potential and electron phase maps. The central
problem of quantitative EH is that at the surfaces of the
thin TEM lamellae a defect-induced pinning occurs, which
alters the phase contrast. Therefore, we calibrated the
electron optical phase maps using a delta-doped layer at the
GaN buffer/substrate interface by determining the energy of
the pinning level at the surface to 0.69 eV above the VBM
(consistent with pinning by nitrogen vacancies). The such
calibrated EH provides quantification of the key interface
properties: The biaxially relaxed In0.05Ga0.95N/
Al0.06Ga0.94N interface exhibits polarization and electron
affinity changes as theoretically expected. However, at the
Al0.06Ga0.94N/GaN interface anomalous lattice relaxations
and vanishing polarization and electron affinity changes
occur, whose underlying physical origin is anticipated to be
total energy minimization by the minimization of Coulomb
interactions between the polarization-induced interface
charges.},
month = {Jan},
date = {2023-01-15},
organization = {48th Conference on the Physics and
Chemistry of Surfaces and Interfaces,
Los Angeles (USA), 15 Jan 2023 - 19 Jan
2023},
subtyp = {Plenary/Keynote},
cin = {ER-C-1},
cid = {I:(DE-Juel1)ER-C-1-20170209},
pnm = {5351 - Platform for Correlative, In Situ and Operando
Characterization (POF4-535)},
pid = {G:(DE-HGF)POF4-5351},
typ = {PUB:(DE-HGF)6},
url = {https://juser.fz-juelich.de/record/972158},
}