Influence of Point Defects Concentration on Densification Process and Optical Properties of Sintered ZnO Ceramics

2015
Authors
Marković, Smilja
Stanković, Ana

Veselinović, Ljiljana

Belošević Čavor, Jelena

Škapin, Srečo Davor

Stojadinović, Stevan

Rac, Vladislav

Lević, Steva

Janković Častvan, Ivona

Uskoković, Dragan

Conference object (Published version)
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Zinc oxide is one of the most studied materials due to its potential applications in electronics, optoelectronics and spintronics. In the forms of single crystal and thin-film ZnO could be used as UV and blue light emitter, while sintered ZnO-based ceramics are important as varistors, thermistors or wide-band gap semiconductors. Intrinsic defects, such as vacancies, interstitials and antisites, in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Thus, understanding the behavior of intrinsic defects during densification of ZnO ceramics as well as correlation of the defects with band gap energy of final product is important to its application in opto-electronic devices.
In this study, the influence of point defects concentration on the densification process and optical properties of ZnO sintered ceramics was investigated. To obtain ZnO sintered ceramics with variety of point defects concentration we employed two starting powders with a different ...crystal structure ordering, as well different morphology and specific surface area. Sinterability of the powders was investigated by thermo mechanical analyzer; shrinkage data, collected in axial (h) direction during non-isothermal sintering with heating rates of 5, 10 and 20 °/min, were used to calculate activation energy of sintering process. Sintering of uniaxially pressed (P = 100 MPa) cylindrical compacts (ø 6 mm and h ≈ 3 mm) were done in air atmosphere by heating rate of 10 °/min up to 1100 and 1200 °C, and dwell time of 2 h. To study a crystal structure of the sintered samples XRD and Raman spectroscopy were used, for microstructural investigation field emission scanning electron micrographs were recorded while optical properties were determined by UV-Vis diffuse reflectance and photoluminescence spectroscopy. A detailed study shows that point defect strongly influenced densification process as well optical properties. Sintered ZnO ceramic with a high crystal defect concentration and nanosized grains shows band gap energy of about 2 eV while band gap energy increased with a decrease of defect concentration.
Keywords:
zinc oxide / sintering / optical propertiesSource:
Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015, 2015, 61-61Publisher:
- Belgrade : Materials Research Society of Serbia
Funding / projects:
Institution/Community
Институт техничких наука САНУ / Institute of Technical Sciences of SASATY - CONF AU - Marković, Smilja AU - Stanković, Ana AU - Veselinović, Ljiljana AU - Belošević Čavor, Jelena AU - Škapin, Srečo Davor AU - Stojadinović, Stevan AU - Rac, Vladislav AU - Lević, Steva AU - Janković Častvan, Ivona AU - Uskoković, Dragan PY - 2015 UR - https://dais.sanu.ac.rs/123456789/831 AB - Zinc oxide is one of the most studied materials due to its potential applications in electronics, optoelectronics and spintronics. In the forms of single crystal and thin-film ZnO could be used as UV and blue light emitter, while sintered ZnO-based ceramics are important as varistors, thermistors or wide-band gap semiconductors. Intrinsic defects, such as vacancies, interstitials and antisites, in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Thus, understanding the behavior of intrinsic defects during densification of ZnO ceramics as well as correlation of the defects with band gap energy of final product is important to its application in opto-electronic devices. In this study, the influence of point defects concentration on the densification process and optical properties of ZnO sintered ceramics was investigated. To obtain ZnO sintered ceramics with variety of point defects concentration we employed two starting powders with a different crystal structure ordering, as well different morphology and specific surface area. Sinterability of the powders was investigated by thermo mechanical analyzer; shrinkage data, collected in axial (h) direction during non-isothermal sintering with heating rates of 5, 10 and 20 °/min, were used to calculate activation energy of sintering process. Sintering of uniaxially pressed (P = 100 MPa) cylindrical compacts (ø 6 mm and h ≈ 3 mm) were done in air atmosphere by heating rate of 10 °/min up to 1100 and 1200 °C, and dwell time of 2 h. To study a crystal structure of the sintered samples XRD and Raman spectroscopy were used, for microstructural investigation field emission scanning electron micrographs were recorded while optical properties were determined by UV-Vis diffuse reflectance and photoluminescence spectroscopy. A detailed study shows that point defect strongly influenced densification process as well optical properties. Sintered ZnO ceramic with a high crystal defect concentration and nanosized grains shows band gap energy of about 2 eV while band gap energy increased with a decrease of defect concentration. PB - Belgrade : Materials Research Society of Serbia C3 - Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015 T1 - Influence of Point Defects Concentration on Densification Process and Optical Properties of Sintered ZnO Ceramics SP - 61 EP - 61 UR - https://hdl.handle.net/21.15107/rcub_dais_831 ER -
@conference{ author = "Marković, Smilja and Stanković, Ana and Veselinović, Ljiljana and Belošević Čavor, Jelena and Škapin, Srečo Davor and Stojadinović, Stevan and Rac, Vladislav and Lević, Steva and Janković Častvan, Ivona and Uskoković, Dragan", year = "2015", abstract = "Zinc oxide is one of the most studied materials due to its potential applications in electronics, optoelectronics and spintronics. In the forms of single crystal and thin-film ZnO could be used as UV and blue light emitter, while sintered ZnO-based ceramics are important as varistors, thermistors or wide-band gap semiconductors. Intrinsic defects, such as vacancies, interstitials and antisites, in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Thus, understanding the behavior of intrinsic defects during densification of ZnO ceramics as well as correlation of the defects with band gap energy of final product is important to its application in opto-electronic devices. In this study, the influence of point defects concentration on the densification process and optical properties of ZnO sintered ceramics was investigated. To obtain ZnO sintered ceramics with variety of point defects concentration we employed two starting powders with a different crystal structure ordering, as well different morphology and specific surface area. Sinterability of the powders was investigated by thermo mechanical analyzer; shrinkage data, collected in axial (h) direction during non-isothermal sintering with heating rates of 5, 10 and 20 °/min, were used to calculate activation energy of sintering process. Sintering of uniaxially pressed (P = 100 MPa) cylindrical compacts (ø 6 mm and h ≈ 3 mm) were done in air atmosphere by heating rate of 10 °/min up to 1100 and 1200 °C, and dwell time of 2 h. To study a crystal structure of the sintered samples XRD and Raman spectroscopy were used, for microstructural investigation field emission scanning electron micrographs were recorded while optical properties were determined by UV-Vis diffuse reflectance and photoluminescence spectroscopy. A detailed study shows that point defect strongly influenced densification process as well optical properties. Sintered ZnO ceramic with a high crystal defect concentration and nanosized grains shows band gap energy of about 2 eV while band gap energy increased with a decrease of defect concentration.", publisher = "Belgrade : Materials Research Society of Serbia", journal = "Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015", title = "Influence of Point Defects Concentration on Densification Process and Optical Properties of Sintered ZnO Ceramics", pages = "61-61", url = "https://hdl.handle.net/21.15107/rcub_dais_831" }
Marković, S., Stanković, A., Veselinović, L., Belošević Čavor, J., Škapin, S. D., Stojadinović, S., Rac, V., Lević, S., Janković Častvan, I.,& Uskoković, D.. (2015). Influence of Point Defects Concentration on Densification Process and Optical Properties of Sintered ZnO Ceramics. in Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015 Belgrade : Materials Research Society of Serbia., 61-61. https://hdl.handle.net/21.15107/rcub_dais_831
Marković S, Stanković A, Veselinović L, Belošević Čavor J, Škapin SD, Stojadinović S, Rac V, Lević S, Janković Častvan I, Uskoković D. Influence of Point Defects Concentration on Densification Process and Optical Properties of Sintered ZnO Ceramics. in Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015. 2015;:61-61. https://hdl.handle.net/21.15107/rcub_dais_831 .
Marković, Smilja, Stanković, Ana, Veselinović, Ljiljana, Belošević Čavor, Jelena, Škapin, Srečo Davor, Stojadinović, Stevan, Rac, Vladislav, Lević, Steva, Janković Častvan, Ivona, Uskoković, Dragan, "Influence of Point Defects Concentration on Densification Process and Optical Properties of Sintered ZnO Ceramics" in Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015 (2015):61-61, https://hdl.handle.net/21.15107/rcub_dais_831 .