Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studies
To realize the many potential applications of ZnO films, it is vital to produce films with high optical quality that exhibit strong UV luminescence. By combining annealing at an optimal temperature followed by the deposition of a coating, one can achieve a significant enhancement of photoluminescenc...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
AIP Publishing LLC
2020-08-01
|
| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/5.0016510 |
| _version_ | 1828526574811480064 |
|---|---|
| author | Jeffrey Lapp Dinesh Thapa Jesse Huso Amrah Canul M. Grant Norton Matthew D. McCluskey Leah Bergman |
| author_facet | Jeffrey Lapp Dinesh Thapa Jesse Huso Amrah Canul M. Grant Norton Matthew D. McCluskey Leah Bergman |
| author_sort | Jeffrey Lapp |
| collection | DOAJ |
| description | To realize the many potential applications of ZnO films, it is vital to produce films with high optical quality that exhibit strong UV luminescence. By combining annealing at an optimal temperature followed by the deposition of a coating, one can achieve a significant enhancement of photoluminescence (PL). The effectiveness of the coating over time is a crucial point to be considered. Three types of coating materials were investigated: MgO, SiO2, and Al2O3. Due to its strong bond energy, MgO was found to be the most effective coating material for passivation of the surfaces of the ZnO films; SiO2 was the second best. The UV-PL intensity of MgO coated ZnO was found to increase by a factor of 52 relative to an uncoated film. The effectiveness of the coatings exhibited a linear correlation with their bond energies and is discussed in terms of competing mechanisms to surface passivation such as the adsorption of OH-groups; these can act as surface traps and diminish the UV-PL intensity. Annealing at 900 °C prior to the deposition of the coating was found to be an important step in realizing the optimal performance of the coating due to the reduction of Zn interstitials accompanied by improved crystallinity. Exposure to the environment, up to 294 days, results in the degradation of the UV-PL of the MgO coated film; this effect was not observed for the film coated with SiO2. This effect is discussed in terms of the strong reactivity of MgO with environmental contaminants from the OH-groups. |
| first_indexed | 2024-12-11T21:26:49Z |
| format | Article |
| id | doaj.art-7321752b8bb94d7889109c4b589dc3bf |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-12-11T21:26:49Z |
| publishDate | 2020-08-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-7321752b8bb94d7889109c4b589dc3bf2022-12-22T00:50:19ZengAIP Publishing LLCAIP Advances2158-32262020-08-01108085217085217-810.1063/5.0016510Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studiesJeffrey Lapp0Dinesh Thapa1Jesse Huso2Amrah Canul3M. Grant Norton4Matthew D. McCluskey5Leah Bergman6Department of Physics, University of Idaho, Moscow, Idaho 83844-0903, USADepartment of Physics, University of Idaho, Moscow, Idaho 83844-0903, USADepartment of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USADepartment of Physics, University of Idaho, Moscow, Idaho 83844-0903, USASchool of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920, USADepartment of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USADepartment of Physics, University of Idaho, Moscow, Idaho 83844-0903, USATo realize the many potential applications of ZnO films, it is vital to produce films with high optical quality that exhibit strong UV luminescence. By combining annealing at an optimal temperature followed by the deposition of a coating, one can achieve a significant enhancement of photoluminescence (PL). The effectiveness of the coating over time is a crucial point to be considered. Three types of coating materials were investigated: MgO, SiO2, and Al2O3. Due to its strong bond energy, MgO was found to be the most effective coating material for passivation of the surfaces of the ZnO films; SiO2 was the second best. The UV-PL intensity of MgO coated ZnO was found to increase by a factor of 52 relative to an uncoated film. The effectiveness of the coatings exhibited a linear correlation with their bond energies and is discussed in terms of competing mechanisms to surface passivation such as the adsorption of OH-groups; these can act as surface traps and diminish the UV-PL intensity. Annealing at 900 °C prior to the deposition of the coating was found to be an important step in realizing the optimal performance of the coating due to the reduction of Zn interstitials accompanied by improved crystallinity. Exposure to the environment, up to 294 days, results in the degradation of the UV-PL of the MgO coated film; this effect was not observed for the film coated with SiO2. This effect is discussed in terms of the strong reactivity of MgO with environmental contaminants from the OH-groups.http://dx.doi.org/10.1063/5.0016510 |
| spellingShingle | Jeffrey Lapp Dinesh Thapa Jesse Huso Amrah Canul M. Grant Norton Matthew D. McCluskey Leah Bergman Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studies AIP Advances |
| title | Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studies |
| title_full | Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studies |
| title_fullStr | Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studies |
| title_full_unstemmed | Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studies |
| title_short | Enhancement of the ultraviolet photoluminescence of ZnO films: Coatings, annealing, and environmental exposure studies |
| title_sort | enhancement of the ultraviolet photoluminescence of zno films coatings annealing and environmental exposure studies |
| url | http://dx.doi.org/10.1063/5.0016510 |
| work_keys_str_mv | AT jeffreylapp enhancementoftheultravioletphotoluminescenceofznofilmscoatingsannealingandenvironmentalexposurestudies AT dineshthapa enhancementoftheultravioletphotoluminescenceofznofilmscoatingsannealingandenvironmentalexposurestudies AT jessehuso enhancementoftheultravioletphotoluminescenceofznofilmscoatingsannealingandenvironmentalexposurestudies AT amrahcanul enhancementoftheultravioletphotoluminescenceofznofilmscoatingsannealingandenvironmentalexposurestudies AT mgrantnorton enhancementoftheultravioletphotoluminescenceofznofilmscoatingsannealingandenvironmentalexposurestudies AT matthewdmccluskey enhancementoftheultravioletphotoluminescenceofznofilmscoatingsannealingandenvironmentalexposurestudies AT leahbergman enhancementoftheultravioletphotoluminescenceofznofilmscoatingsannealingandenvironmentalexposurestudies |