Abstract
We report continuous wave operation of SiO2 sandwiched colloidal CdSe/ZnS quantum-dot microdisk lasers at room temperature. The SiO2 sandwiched quantum dot structure is formed first and then the disk patterns are defined by e-beam lithography. The benefits of introducing the sandwich structure are two folds: one to increase the confinement factor and the other to reduce the photo-oxidation of quantum dots. The luminescence stability of CdSe/ZnS quantum dots is much improved after they are sandwiched in silicon dioxide. We observe whispering gallery modes spatially and spectrally in the microdisks. We also fabricated Si3N4 microdisks for comparison. The result shows that Si3N4 microdisks are severely damaged when operating under continuous wave excitation while SiO2 microdisks demonstrate stable lasing behavior at the same excitation condition. Therefore, SiO2 microdisks are more suitable for high excitation and/or continuous wave applications such as lasers. This device structure shows great potentials to be applied to other wavelength in the visible range.
Published Version
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