研究目的
Investigating the origin of the enhancement of defect-related visible emission in annealed ZnO micropods.
研究成果
The annealing process leads to nitrogen doping of ZnO micropods, formation of structural defects at their surface, and improved crystal quality. These changes result in a drastic increase in defect-related visible emission, attributed to an efficient nonradiative energy transfer between Y-band states and defect states. The study provides insights into controlling the UV-to-visible emission ratio in ZnO micropods through annealing.
研究不足
The study is limited to the analysis of ZnO micropods grown by CBD and annealed at 900°C. The mechanisms proposed are based on the observed changes in PL and Raman spectra, which may not account for all possible defect interactions in ZnO.
1:Experimental Design and Method Selection:
ZnO micropods were synthesized using low-temperature chemical bath deposition (CBD) and subsequently annealed at 900°C under nitrogen atmosphere. The study involved structural and optical characterization to understand the changes induced by annealing.
2:Sample Selection and Data Sources:
Undoped p-type (100) silicon wafers were used as substrates for depositing the micropods. The samples included as-grown and annealed ZnO micropods.
3:List of Experimental Equipment and Materials:
Scanning electron microscope (SEM, HITACHI S-3400N, 30 kV), Philips powder X-ray diffractometer with Cu Kα line, He-Cd laser (325 nm) for PL studies, CCD camera as detector, and micro-Raman setup with 514 nm laser wavelength.
4:Experimental Procedures and Operational Workflow:
The growth of ZnO micropods was conducted by CBD. Annealing was performed in a rapid thermal annealing system. Structural and optical characterizations were carried out using SEM, XRD, PL, and Raman spectroscopy.
5:Data Analysis Methods:
XRD data were analyzed using the Scherrer equation for crystallite size determination. PL spectra were analyzed to understand the emission mechanisms, and Raman spectra were used to identify defects and structural changes.
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