SPIN-COATED POLYMER MICROCAVITY FOR LIGHT EMITTERS AND LASERS

摘要

A spin-coated polymer microcavity for light emitters and lasers producing enhancement of spontaneous emission rate from colloidal CdSe/ZnS core/shell quantum dots embedded in a one dimensional polymer microcavity structure at room temperature. The polymer microcavity structures are fabricated using spin coating. Alternating layers of polymers of two different refractive indices were stacked to form the Distributed Bragg reflectors (DBRs). To achieve high reflectivity, the polymers for the DBR structures were chosen so that they have a relatively high refractive index ratio. The high and low refractive index polymers chosen were poly-N(vinylcarbazole) (PVK) and poly acrylic acid (PAA), with refractive indices of 1.683 and 1.420 at 600 nm, respectively. Thin films of quarter wavelength thickness of the two polymers are alternately spin coated on a glass substrate to make the DBR structures. Greater than 90% reflectivity is obtained using ten periods of the structure. A PVK cavity layer of ? thickness embedded with CdSe/ZnS core/shell quantum dots is sandwiched between two of these DBRs to form the entire microcavity structure. The bottom and top DBRs comprise ten and five periods, respectively.