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Excitonic properties of layer-by-layer CVD grown ZnO hexagonal microdisks
Mrinal K Sikdar1, Bhabesh Sarangi1, Pratap K Sahoo1
1School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar, HBNI, Jatni, Odisha-752050, India.
Abstract:
We have investigated the excitonic properties of highly crystalline ZnO hexagonal microdisks grown by the chemical vapour deposition technique. It was observed that a suitable negative catalyst like chlorine suppresses the crystal growth along the (0001) direction. We propose a qualitative model for the experimentally observed layer-by-layer growth mechanism of the microdisks. Room temperature photoluminescence of the microdisks manifests a very high near-band-edge (NBE) emission peak in the UV region and a minor defect peak in the visible region. The excitonic emission of the microdisks was studied using the low-temperature photoluminescence down to 83 K, which reveals a surface exciton peak in the NBE region and well fitted higher-order phonon replicas.
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