A solid state light emitting device composed of the 10 nm thickness zirconium-doped hafnium oxide high-k gate dielectric with or without an embedded nanocrystalline ZnO layer has been fabricated and studied. The emission spectrum, which extended from visible light to IR, was broadened and the intensity was increased with the embedding of a nanocrystalline ZnO layer. The mechanisms of light emission and enhancement were investigated and explained with defect generation process in the film. This kind of device is easily prepared by the IC compatible process. There are many potential applications of this kind of device.
Metal-oxide-semiconductor capacitors made of the nanocrystalline cadmium selenide nc-CdSe embedded Zr-doped HfO2 high-k stack on the p-type silicon wafer have been fabricated and studied for their charge trapping, detrapping, and retention characteristics. Both holes and electrons can be trapped to the nanocrystal-embedded dielectric stack depending on the polarity of the applied gate voltage. With the same magnitude of applied gate voltage, the sample can trap more holes than electrons. A small amount of holes are loosely trapped at the nc-CdSe/high-k interface and the remaining holes are strongly trapped to the bulk nanocrystalline CdSe site. Charges trapped to the nanocrystals caused the Coulomb blockade effect in the leakage current vs. voltage curve, which is not observed in the control sample. The addition of the nanocrystals to the dielectric film changed the defect density and the physical thickness, which are reflected on the leakage current and the breakdown voltage. More than half of the originally trapped holes can be retained in the embedded nanocrystals for more than 10 yr. The nanocrystalline CdSe embedded high-k stack is a useful gate dielectric for this nonvolatile memory device.
Electrical and optical properties of the solid state incandescent light emitting devices made of zirconium doped hafnium oxide high-k films with and without an embedded nanocrystalline CdSe layer on the p-type Si wafer have been studied. The broad band white light was emitted from nano sized conductive paths through the thermal excitation mechanism. Conductive paths formed from the dielectric breakdown have been confirmed from scanning electron microscopic and atomic force microscopic images and the secondary ion mass spectrometric elemental profiles. Si was diffused from the wafer to the device surface through the conductive path during the high temperature light emission process. There are many potential applications of this type of device.
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