TY  - JOUR
AU  - Fischer, Dieter
AU  - Zagorac, Dejan
AU  - Schön, Christian J.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11548
AB  - Zinc oxide shows unique properties which are evident in a wide range of applications: as a transparent conducting oxide, wide-bandgap semiconductor, and piezoelectric device. The starting point for understanding the origin of these properties are the subtle details of the crystal structure of ZnO, and thus elucidating its formation process is essential. The in-situ characterization of films deposited at various temperatures provides an important contribution in this regard, especially since this study reports on ZnO film deposition below room temperature down to -240 ◦C. Systematic investigations on nanocrystalline ZnO films as function of the deposition temperature reveal structural disorders caused by the irregular occupation of oxygen tetrahedra forming dioxygen species in zinc oxide. Three distinct material ranges are identified in the range of deposition temperatures between -240 and 300 ◦C. The most surprising observations are the segregation of zinc next to ZnO particles for films deposited at room temperature and the disappearance of the Raman bands of the ZnO lattice for those deposited above 100 ◦C. On both ends of the investigated deposition temperature scale transparent colorless films are obtained, which form a random frozen solid at low temperatures as well as a highly disordered film at high temperatures. The deposits at -80 ◦C are yellow in color, indicating the presence of superoxide ions. This wide variety in the properties of ZnO is enabled by the high flexibility of the wurtzite structure, which tolerates huge distance variations. This observation and the results presented open up important insights into the behavior of zinc oxide.
T2  - Thin Solid Films
T1  - Fundamental insight into the formation of the zinc oxide crystal structure
VL  - 782
SP  - 140017
DO  - 10.1016/j.tsf.2023.140017
ER  - 

@article{
author = "Fischer, Dieter and Zagorac, Dejan and Schön, Christian J.",
year = "2023",
abstract = "Zinc oxide shows unique properties which are evident in a wide range of applications: as a transparent conducting oxide, wide-bandgap semiconductor, and piezoelectric device. The starting point for understanding the origin of these properties are the subtle details of the crystal structure of ZnO, and thus elucidating its formation process is essential. The in-situ characterization of films deposited at various temperatures provides an important contribution in this regard, especially since this study reports on ZnO film deposition below room temperature down to -240 ◦C. Systematic investigations on nanocrystalline ZnO films as function of the deposition temperature reveal structural disorders caused by the irregular occupation of oxygen tetrahedra forming dioxygen species in zinc oxide. Three distinct material ranges are identified in the range of deposition temperatures between -240 and 300 ◦C. The most surprising observations are the segregation of zinc next to ZnO particles for films deposited at room temperature and the disappearance of the Raman bands of the ZnO lattice for those deposited above 100 ◦C. On both ends of the investigated deposition temperature scale transparent colorless films are obtained, which form a random frozen solid at low temperatures as well as a highly disordered film at high temperatures. The deposits at -80 ◦C are yellow in color, indicating the presence of superoxide ions. This wide variety in the properties of ZnO is enabled by the high flexibility of the wurtzite structure, which tolerates huge distance variations. This observation and the results presented open up important insights into the behavior of zinc oxide.",
journal = "Thin Solid Films",
title = "Fundamental insight into the formation of the zinc oxide crystal structure",
volume = "782",
pages = "140017",
doi = "10.1016/j.tsf.2023.140017"
}

Fischer, D., Zagorac, D.,& Schön, C. J.. (2023). Fundamental insight into the formation of the zinc oxide crystal structure. in Thin Solid Films, 782, 140017.
https://doi.org/10.1016/j.tsf.2023.140017

Fischer D, Zagorac D, Schön CJ. Fundamental insight into the formation of the zinc oxide crystal structure. in Thin Solid Films. 2023;782:140017.
doi:10.1016/j.tsf.2023.140017 .

Fischer, Dieter, Zagorac, Dejan, Schön, Christian J., "Fundamental insight into the formation of the zinc oxide crystal structure" in Thin Solid Films, 782 (2023):140017,
https://doi.org/10.1016/j.tsf.2023.140017 . .

TY  - JOUR
AU  - Christian Schön, J.
AU  - Fischer, Dieter
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12863
AB  - The development of new materials in an efficient fashion requires progress both in the computational search for promising targets and in the design of suitable synthesis routes by a combined effort of theory and experiment. This applies not only to bulk materials but also to low- dimensional systems such as thin films and monolayers. In this presentation, we will discuss some of the methodological features specific to the prediction and synthesis of (meta)stable (quasi)-low- dimensional systems, together with examples of structure prediction and modeling for crystalline and amorphous atom- and molecule-based monolayers and thin films. This is complemented by direct comparisons with experiments, and the discussion of additional thin film experiments that focus on new structural insights in seemingly completely understood systems like gallium and ZnO films.
T2  - Journal of Innovative Materials in Extreme Conditions
T1  - Thin Films and Monolayers – Prediction, Modeling, and Experiments
VL  - 4
IS  - 2
SP  - 52
EP  - 76
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12863
ER  - 

@article{
author = "Christian Schön, J. and Fischer, Dieter",
year = "2023",
abstract = "The development of new materials in an efficient fashion requires progress both in the computational search for promising targets and in the design of suitable synthesis routes by a combined effort of theory and experiment. This applies not only to bulk materials but also to low- dimensional systems such as thin films and monolayers. In this presentation, we will discuss some of the methodological features specific to the prediction and synthesis of (meta)stable (quasi)-low- dimensional systems, together with examples of structure prediction and modeling for crystalline and amorphous atom- and molecule-based monolayers and thin films. This is complemented by direct comparisons with experiments, and the discussion of additional thin film experiments that focus on new structural insights in seemingly completely understood systems like gallium and ZnO films.",
journal = "Journal of Innovative Materials in Extreme Conditions",
title = "Thin Films and Monolayers – Prediction, Modeling, and Experiments",
volume = "4",
number = "2",
pages = "52-76",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12863"
}

Christian Schön, J.,& Fischer, D.. (2023). Thin Films and Monolayers – Prediction, Modeling, and Experiments. in Journal of Innovative Materials in Extreme Conditions, 4(2), 52-76.
https://hdl.handle.net/21.15107/rcub_vinar_12863

Christian Schön J, Fischer D. Thin Films and Monolayers – Prediction, Modeling, and Experiments. in Journal of Innovative Materials in Extreme Conditions. 2023;4(2):52-76.
https://hdl.handle.net/21.15107/rcub_vinar_12863 .

Christian Schön, J., Fischer, Dieter, "Thin Films and Monolayers – Prediction, Modeling, and Experiments" in Journal of Innovative Materials in Extreme Conditions, 4, no. 2 (2023):52-76,
https://hdl.handle.net/21.15107/rcub_vinar_12863 .

TY  - JOUR
AU  - Fischer, Dieter
AU  - Zagorac, Dejan
AU  - Schön, Christian J.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10419
AB  - Zinc oxide exhibits unique properties that are reflected in a wide variety of applications, particularly in the field of transparent, conductive films. However, less attention has been paid to their color. Here, we present the synthesis of yellow-gray ZnO films at room temperature by femtosecond pulsed laser deposition. In situ Raman investigations of these polycrystalline ZnO films reveal the existence of superoxide ions, O2−, in zinc oxide, which are responsible for the yellow color, and are also detected in ZnO powder and single crystals. In addition, further dioxygen species are identified in the samples, including the O2-molecule. The negative charge excess caused by the dioxygen species creates metallic zinc as a byproduct. Structural analysis reveals an unforced realization of the dioxygen species in the ZnO lattice. Density functional theory (DFT) calculations support the assumed structural displacements as well as the observed, unexpected Raman bands. These results open up completely new insights into the behavior of ZnO.
T2  - Journal of Raman Spectroscopy
T1  - The presence of superoxide ions and related dioxygen species in zinc oxide—A structural characterization by in situ Raman spectroscopy
VL  - n/a
IS  - n/a
DO  - 10.1002/jrs.6441
ER  - 

@article{
author = "Fischer, Dieter and Zagorac, Dejan and Schön, Christian J.",
year = "2022",
abstract = "Zinc oxide exhibits unique properties that are reflected in a wide variety of applications, particularly in the field of transparent, conductive films. However, less attention has been paid to their color. Here, we present the synthesis of yellow-gray ZnO films at room temperature by femtosecond pulsed laser deposition. In situ Raman investigations of these polycrystalline ZnO films reveal the existence of superoxide ions, O2−, in zinc oxide, which are responsible for the yellow color, and are also detected in ZnO powder and single crystals. In addition, further dioxygen species are identified in the samples, including the O2-molecule. The negative charge excess caused by the dioxygen species creates metallic zinc as a byproduct. Structural analysis reveals an unforced realization of the dioxygen species in the ZnO lattice. Density functional theory (DFT) calculations support the assumed structural displacements as well as the observed, unexpected Raman bands. These results open up completely new insights into the behavior of ZnO.",
journal = "Journal of Raman Spectroscopy",
title = "The presence of superoxide ions and related dioxygen species in zinc oxide—A structural characterization by in situ Raman spectroscopy",
volume = "n/a",
number = "n/a",
doi = "10.1002/jrs.6441"
}

Fischer, D., Zagorac, D.,& Schön, C. J.. (2022). The presence of superoxide ions and related dioxygen species in zinc oxide—A structural characterization by in situ Raman spectroscopy. in Journal of Raman Spectroscopy, n/a(n/a).
https://doi.org/10.1002/jrs.6441

Fischer D, Zagorac D, Schön CJ. The presence of superoxide ions and related dioxygen species in zinc oxide—A structural characterization by in situ Raman spectroscopy. in Journal of Raman Spectroscopy. 2022;n/a(n/a).
doi:10.1002/jrs.6441 .

Fischer, Dieter, Zagorac, Dejan, Schön, Christian J., "The presence of superoxide ions and related dioxygen species in zinc oxide—A structural characterization by in situ Raman spectroscopy" in Journal of Raman Spectroscopy, n/a, no. n/a (2022),
https://doi.org/10.1002/jrs.6441 . .