Encapsulating Quantum Dots into ZnO Nanorods for Advanced photonics and Laser Applications
Technical Report,16 Jun 2014,15 Jun 2016
QUEENSLAND UNIV OF TECHNOLOGY BRISBANE (AUSTRALIA) BRISBANE United States
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Colloidal quantum dots are promising for new-generation light-emitting devices and lasers. By encapsulating quantum dots with various emission colours into single-crystal ZnO nanomicrorods grown in chemical bath we obtain Fabry-Perot type resonances of the light emitted when stimulated by an external laser. The hexagonal structure of ZnO crystals act as optical cavity, and due to the waveguide effect partial photons would propagate along the nanomicrorods axis direction. In order to grow patterned and ordered ZnO nanomicrorodsfor Fabry-Perot type resonance, we developed a microsphere lithography technique to produce shadow masks onto GaN substrates. In this way we have been able to grow vertical ZnO nanomicrorods arrays with controllable interspace and size by a simple aqueous solution method. We demonstrate the encapsulation of quantum dots QD into the ZnO nanomicrorods by a regrowth process. The optical properties of the single rod, and of the ensemble of the structures are measured by photoluminescence, showing a clear enhancement of the light emitted by QD adsorbed on the rod surface, and a wavelength shift coupled to an intensity reduction after the encapsulation. This study is the first step towards the development of color-tunable lighting devices and lasers based on micronanorods, and will open the way to a plethora of applications in optoelectronics, medicine, and gas sensing.