TY  - JOUR
AU  - Rašković-Lovre, Željka
AU  - Mongstad, Trygve T.
AU  - Karazhanov, Smagul
AU  - You, Chang Chuan
AU  - Lindberg, Simon
AU  - Lelis, Martynas
AU  - Milčius, Darius
AU  - Deledda, Stefano
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1825
AB  - It is well known that optical properties of Mg-Ni-H films can be tuned by hydrogen uptake from Mg-Ni-H and upload into Mg-Ni systems. In this work we show that modulation of optical properties of Mg-Ni-H can take place as a result of thermal processing in air as well. When reactively sputter deposited semiconducting Mg-Ni-H films are annealed at temperatures of 200 degrees C-300 degrees C in air, gradual band gap change from 1.6 to 2.04 eV occurs followed by change in optical appearance, from brown, to orange and, subsequently, to yellow. We investigate this phenomenon using optical and structural characterization tools, and link the changes to an atomic rearrangement and a structure reordering of the [NiH4]4-complex. The films are x-ray amorphous up to 280 degrees C, where above this temperature an increase in crystallite size and establishing of long-range order lead to a formation of the cubic crystalline phase of Mg2NiH4. Also, the results suggest that even though annealing was conducted in air, no oxidation or other changes in chemical composition of the bulk of the film occurred. Therefore, the band gap of this semiconductor can be tuned permanently by heat treatment, in the range from 1.6 to 2 eV.
T2  - Materials Research Express
T1  - Annealing-induced structural rearrangement and optical band gap change in Mg-Ni-H thin films
VL  - 4
IS  - 1
DO  - 10.1088/2053-1591/4/1/016405
ER  - 

@article{
author = "Rašković-Lovre, Željka and Mongstad, Trygve T. and Karazhanov, Smagul and You, Chang Chuan and Lindberg, Simon and Lelis, Martynas and Milčius, Darius and Deledda, Stefano",
year = "2017",
abstract = "It is well known that optical properties of Mg-Ni-H films can be tuned by hydrogen uptake from Mg-Ni-H and upload into Mg-Ni systems. In this work we show that modulation of optical properties of Mg-Ni-H can take place as a result of thermal processing in air as well. When reactively sputter deposited semiconducting Mg-Ni-H films are annealed at temperatures of 200 degrees C-300 degrees C in air, gradual band gap change from 1.6 to 2.04 eV occurs followed by change in optical appearance, from brown, to orange and, subsequently, to yellow. We investigate this phenomenon using optical and structural characterization tools, and link the changes to an atomic rearrangement and a structure reordering of the [NiH4]4-complex. The films are x-ray amorphous up to 280 degrees C, where above this temperature an increase in crystallite size and establishing of long-range order lead to a formation of the cubic crystalline phase of Mg2NiH4. Also, the results suggest that even though annealing was conducted in air, no oxidation or other changes in chemical composition of the bulk of the film occurred. Therefore, the band gap of this semiconductor can be tuned permanently by heat treatment, in the range from 1.6 to 2 eV.",
journal = "Materials Research Express",
title = "Annealing-induced structural rearrangement and optical band gap change in Mg-Ni-H thin films",
volume = "4",
number = "1",
doi = "10.1088/2053-1591/4/1/016405"
}

Rašković-Lovre, Ž., Mongstad, T. T., Karazhanov, S., You, C. C., Lindberg, S., Lelis, M., Milčius, D.,& Deledda, S.. (2017). Annealing-induced structural rearrangement and optical band gap change in Mg-Ni-H thin films. in Materials Research Express, 4(1).
https://doi.org/10.1088/2053-1591/4/1/016405

Rašković-Lovre Ž, Mongstad TT, Karazhanov S, You CC, Lindberg S, Lelis M, Milčius D, Deledda S. Annealing-induced structural rearrangement and optical band gap change in Mg-Ni-H thin films. in Materials Research Express. 2017;4(1).
doi:10.1088/2053-1591/4/1/016405 .

Rašković-Lovre, Željka, Mongstad, Trygve T., Karazhanov, Smagul, You, Chang Chuan, Lindberg, Simon, Lelis, Martynas, Milčius, Darius, Deledda, Stefano, "Annealing-induced structural rearrangement and optical band gap change in Mg-Ni-H thin films" in Materials Research Express, 4, no. 1 (2017),
https://doi.org/10.1088/2053-1591/4/1/016405 . .

TY  - JOUR
AU  - Milčius, Darius
AU  - Grbović-Novaković, Jasmina
AU  - Zostautiene, R.
AU  - Lelis, Martynas
AU  - Girdzevicius, D.
AU  - Urbonavicius, M.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/733
AB  - Contrary to traditional methods including top layer catalyst deposition and ex-situ hydrogenation in current study Mg-H films were synthesized using magnetron sputtering in Ar+ atmosphere and their in-situ hydrogenation in magnetron induced hydrogen plasma. XRD analysis of hydrogenated Mg-H films revealed changes of preferred crystallographic orientation. After 1-3 h of in-situ plasma hydrogenation XRD does not indicate presence of any crystalline MgH2 phase but it is observed after 5 h. The appearance of significant amount of crystalline MgH2 phase after prolonged time of in-situ hydrogenation presupposed that samples without clear expression of MgH2 crystal phase might still have hydrogen rich amorphous Mg phase which is not observable by XRD. The analysis of predicted hydrogen containing phase was performed using combination of conventional SEM; AFM, Q-Q XRD, GI-XRD and XPS analysis techniques. The obtained data of hydrogen containing phase distribution at the surface of the samples and its distribution depth profiles are presented together with considerations related to the efficiency of the proposed in-situ hydrogenation approach and combined analysis methods. (C) 2015 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Combined XRD and XPS analysis of ex-situ and in-situ plasma hydrogenated magnetron sputtered Mg films
VL  - 647
SP  - 790
EP  - 796
DO  - 10.1016/j.jallcom.2015.05.151
ER  - 

@article{
author = "Milčius, Darius and Grbović-Novaković, Jasmina and Zostautiene, R. and Lelis, Martynas and Girdzevicius, D. and Urbonavicius, M.",
year = "2015",
abstract = "Contrary to traditional methods including top layer catalyst deposition and ex-situ hydrogenation in current study Mg-H films were synthesized using magnetron sputtering in Ar+ atmosphere and their in-situ hydrogenation in magnetron induced hydrogen plasma. XRD analysis of hydrogenated Mg-H films revealed changes of preferred crystallographic orientation. After 1-3 h of in-situ plasma hydrogenation XRD does not indicate presence of any crystalline MgH2 phase but it is observed after 5 h. The appearance of significant amount of crystalline MgH2 phase after prolonged time of in-situ hydrogenation presupposed that samples without clear expression of MgH2 crystal phase might still have hydrogen rich amorphous Mg phase which is not observable by XRD. The analysis of predicted hydrogen containing phase was performed using combination of conventional SEM; AFM, Q-Q XRD, GI-XRD and XPS analysis techniques. The obtained data of hydrogen containing phase distribution at the surface of the samples and its distribution depth profiles are presented together with considerations related to the efficiency of the proposed in-situ hydrogenation approach and combined analysis methods. (C) 2015 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Combined XRD and XPS analysis of ex-situ and in-situ plasma hydrogenated magnetron sputtered Mg films",
volume = "647",
pages = "790-796",
doi = "10.1016/j.jallcom.2015.05.151"
}

Milčius, D., Grbović-Novaković, J., Zostautiene, R., Lelis, M., Girdzevicius, D.,& Urbonavicius, M.. (2015). Combined XRD and XPS analysis of ex-situ and in-situ plasma hydrogenated magnetron sputtered Mg films. in Journal of Alloys and Compounds, 647, 790-796.
https://doi.org/10.1016/j.jallcom.2015.05.151

Milčius D, Grbović-Novaković J, Zostautiene R, Lelis M, Girdzevicius D, Urbonavicius M. Combined XRD and XPS analysis of ex-situ and in-situ plasma hydrogenated magnetron sputtered Mg films. in Journal of Alloys and Compounds. 2015;647:790-796.
doi:10.1016/j.jallcom.2015.05.151 .

Milčius, Darius, Grbović-Novaković, Jasmina, Zostautiene, R., Lelis, Martynas, Girdzevicius, D., Urbonavicius, M., "Combined XRD and XPS analysis of ex-situ and in-situ plasma hydrogenated magnetron sputtered Mg films" in Journal of Alloys and Compounds, 647 (2015):790-796,
https://doi.org/10.1016/j.jallcom.2015.05.151 . .