Skin Bond Electron Relaxation Dynamics of Germanium Manipulated by Interactions with H2 , O2 , H2 O, H2 O2 , HF, and Au.
Although germanium performs amazingly well at sites surrounding hetero-coordinated impurities and under-coordinated defects or skins with unusual properties, having important impact on electronic and optical devices, understanding the behavior of the local bonds and electrons at such sites remains a great challenge. Here we show that a combination of density functional theory calculations, zone-resolved X-ray photoelectron spectroscopy, and bond order length strength correlation mechanism has enabled us to clarify the physical origin of the Ge 3d core-level shift for the under-coordinated (111) and (100) skin with and without hetero-coordinated H2 , O2 , H2 O, H2 O2 , HF impurities. The Ge 3d level shifts from 27.579 (for an isolated atom) by 1.381 to 28.960 eV upon bulk formation. Atomic under-coordination shifts the binding energy further to 29.823 eV for the (001) and to 29.713 eV for the (111) monolayer skin. Addition of O2 , HF, H2 O, H2 O2 and Au impurities results in quantum entrapment by different amounts, but H adsorption leads to polarization.
Key Laboratory of Low-dimensional Materials and Application Technology (Ministry of Education), School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, China.
Lihong
L
Wu
Key Laboratory of Low-dimensional Materials and Application Technology (Ministry of Education), School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, China.
Maolin
M
Bo
Key Laboratory of Low-dimensional Materials and Application Technology (Ministry of Education), School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, China.
Yongling
Y
Guo
School of Information and Electronic Engineering, Hunan University of Science and Technology, Hunan, 411201, China.
Yan
Y
Wang
Institute for Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou, 310018, China.
Can
C
Li
Key Laboratory of Low-dimensional Materials and Application Technology (Ministry of Education), School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, China. huangyongli@xtu.edu.cn.
Yongli
Y
Huang
NOVITAS, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore. ecqsun@ntu.edu.sg.
Chang Q
CQ
Sun
core-level shift; density functional theory; germanium; hetero-coordination chemistry; under-coordination physics