1
|
Vijay NK, Maya PN, Mukherjee S, Liedke MO, Butterling M, Attallah AG, Hirschmann E, Wagner A, Benoy MD. Effect of annealing temperature on the structure and optical properties of ZnO thin films. J Phys Condens Matter 2023; 36:135002. [PMID: 38061063 DOI: 10.1088/1361-648x/ad1361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/07/2023] [Indexed: 12/22/2023]
Abstract
The effect of annealing temperature on the microstructure, defects and optical properties of ZnO thin films are investigated using sol-gel based spin coating method for a range of annealing temperatures from 200∘C to 500∘C. The correlation among the microstructure, defects, impurity content and the optical band gap of films of thickness about 10-12 nm is elucidated. The particle size increases and the optical band gap reduces with the annealing temperature. At 200∘C, amorphous films were formed with particle size less than 10 nm with an optical band gap of about 3.41 eV. As the temperature increases the grain size increases and the defect, impurity content as well as the optical band gap reduces. This could be due to the reduction in the lattice strain. For an average grain size of about 35 nm and above, the band gap asymptotically approaches the theoretical value of ZnO (3.37 eV). The photoluminescence (PL) spectra show a systematic red-shift in the excitonic levels corresponding to the variation in the optical band-gap. The defect emission from Zn-vacancies is observed in the PL spectra and are further supported by the positron annihilation measurements.
Collapse
Affiliation(s)
| | - P N Maya
- Institute for Plasma Research, Bhat, Gandhinagar 382428, India
| | - S Mukherjee
- Bhabha Atomic Research Center, Trombay, Mumbai 400085, India
| | - M O Liedke
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstraße, 400, 01328 Dresden, Germany
| | - M Butterling
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstraße, 400, 01328 Dresden, Germany
| | - A G Attallah
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstraße, 400, 01328 Dresden, Germany
| | - E Hirschmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstraße, 400, 01328 Dresden, Germany
| | - A Wagner
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstraße, 400, 01328 Dresden, Germany
| | - M D Benoy
- Mar Athanasius College, Kothamangalam 686666, India
| |
Collapse
|
2
|
Nikitina L, Laptev R, Abzaev Y, Lider A, Ivashutenko A. Positron Spectroscopy of Nanodiamonds after Hydrogen Sorption. Nanomaterials (Basel) 2018; 8:nano8010036. [PMID: 29324712 PMCID: PMC5791123 DOI: 10.3390/nano8010036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 11/16/2022]
Abstract
The structure and defects of nanodiamonds influence the hydrogen sorption capacity. Positronium can be used as a sensor for detecting places with the most efficient capture of hydrogen atoms. Hydrogenation of carbon materials was performed from gas atmosphere. The concentration of hydrogen absorbed by the sample depends on the temperature and pressure. The concentration 1.2 wt % is achieved at the temperature of 243 K and the pressure of 0.6 MPa. The hydrogen saturation of nanodiamonds changes the positron lifetime. Increase of sorption cycle numbers effects the positron lifetime, as well as the parameters of the Doppler broadening of annihilation line. The electron-positron annihilation being a sensitive method, it allows detecting the electron density fluctuation of the carbon material after hydrogen saturation.
Collapse
Affiliation(s)
- Lyudmila Nikitina
- Department of General Physics, Institute of Physics and Technology, Tomsk Polytechnic University, 634000 Tomsk, Russia.
| | - Roman Laptev
- Department of General Physics, Institute of Physics and Technology, Tomsk Polytechnic University, 634000 Tomsk, Russia.
| | - Yuri Abzaev
- Department of Higher Mathematics, Faculty of General Education, Tomsk State University of Architecture and Building, 634003 Tomsk, Russia.
| | - Andrey Lider
- Department of General Physics, Institute of Physics and Technology, Tomsk Polytechnic University, 634000 Tomsk, Russia.
| | - Alexander Ivashutenko
- Department of General Physics, Institute of Physics and Technology, Tomsk Polytechnic University, 634000 Tomsk, Russia.
| |
Collapse
|
3
|
Horodek P, Siemek K, Dryzek J, Wróbel M. Positron Annihilation and Complementary Studies of Copper Sandblasted with Alumina Particles at Different Pressures. Materials (Basel) 2017; 10:ma10121343. [PMID: 29168749 PMCID: PMC5744278 DOI: 10.3390/ma10121343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/05/2017] [Accepted: 11/20/2017] [Indexed: 11/16/2022]
Abstract
Positron annihilation spectroscopy and complementary methods were used to detect changes induced by sandblasting of alumina particles at different pressures varying from 1 to 6 bar in pure well-annealed copper. The positron lifetime measurements revealed existence of dislocations and vacancy clusters in the adjoined surface layer. The presence of retained alumina particles in the copper at the depth below 50 µm was found in the SEM pictures and also in the annihilation line shape parameter profiles measured in the etching experiment. The profiles show us that the total depth of damaged zones induced by sandblasting of alumina particles ranges from 140 µm up to ca. 800 µm and it depends on the applied pressure. The work-hardening of the adjoined surface layer was found in the microhardness measurements at the cross-section of the sandblasted samples.
Collapse
Affiliation(s)
- Paweł Horodek
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland.
- Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980 Dubna, Russia.
| | - Krzysztof Siemek
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland.
- Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980 Dubna, Russia.
| | - Jerzy Dryzek
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland.
| | - Mirosław Wróbel
- Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, 30 Mickiewicza Ave., 90-059 Krakow, Poland.
| |
Collapse
|