TY  - JOUR
AU  - Hajlaoui, Mahdi
AU  - Ponzoni, Stefano
AU  - Deppe, Michael
AU  - Henksmeier, Tobias
AU  - As, Donat Josef
AU  - Reuter, Dirk
AU  - Zentgraf, Thomas
AU  - Springholz, Gunther
AU  - Schneider, Claus Michael
AU  - Cramm, Stefan
AU  - Cinchetti, Mirko
TI  - Extremely low-energy ARPES of quantum well states in cubic-GaN/AlN and GaAs/AlGaAs heterostructures
JO  - Scientific reports
VL  - 11
IS  - 1
SN  - 2045-2322
CY  - [London]
PB  - Macmillan Publishers Limited, part of Springer Nature
M1  - FZJ-2021-05261
SP  - 19081
PY  - 2021
AB  - Quantum well (QW) heterostructures have been extensively used for the realization of a wide range of optical and electronic devices. Exploiting their potential for further improvement and development requires a fundamental understanding of their electronic structure. So far, the most commonly used experimental techniques for this purpose have been all-optical spectroscopy methods that, however, are generally averaging in momentum space. Additional information can be gained by angle-resolved photoelectron spectroscopy (ARPES), which measures the electronic structure with momentum resolution. Here we report on the use of extremely low-energy ARPES (photon energy ~ 7 eV) to increase depth sensitivity and access buried QW states, located at 3 nm and 6 nm below the surface of cubic-GaN/AlN and GaAs/AlGaAs heterostructures, respectively. We find that the QW states in cubic-GaN/AlN can indeed be observed, but not their energy dispersion, because of the high surface roughness. The GaAs/AlGaAs QW states, on the other hand, are buried too deep to be detected by extremely low-energy ARPES. Since the sample surface is much flatter, the ARPES spectra of the GaAs/AlGaAs show distinct features in momentum space, which can be reconducted to the band structure of the topmost surface layer of the QW structure. Our results provide important information about the samples’ properties required to perform extremely low-energy ARPES experiments on electronic states buried in semiconductor heterostructures.
LB  - PUB:(DE-HGF)16
C6  - 34580361
UR  - <Go to ISI:>//WOS:000700619200021
DO  - DOI:10.1038/s41598-021-98569-6
UR  - https://juser.fz-juelich.de/record/903607
ER  -