Uv 3101pc scanning spectrophotometer

A 6-nm Ag layer was initially deposited on c-plane sapphire by electron beam evaporation at a deposition rate of 0.2 nm/s and a pressure of 5   10⁻⁴ Pa, and was subsequently annealed in N₂ atmosphere at 300 °C, 500 °C, 600 °C and 800 °C for 5 min. SiO₂ layers were fabricated by plasma-enhanced chemical vapour deposition (PECVD). For some samples, we grew SiO₂ with various thicknesses beneath the Ag NPs, while for other samples, SiO₂ was grown both beneath and on top of the Ag NPs to form a sandwiched Ag structure. The SiO₂ thickness varies from 0 nm to 20 nm.
The morphologies of the Ag NPs and the SiO₂ cladding layers were measured by SEM. The optical extinction spectra for all samples were measured using a Shimadzu UV-3101PC scanning spectrophotometer.

To prepare ZnO/carbon nanodot hybrid films, the ZnO QDs and carbon nanodots solution were mixed in a series of volume ratio (1:0, 4:1, 2:1, 1:1), and the mixed solution was spun onto c-plane sapphire and then the samples were annealed at 400°C for one hour, and then at 600°C for another hour. In this way, ZnO QD and carbon nanodot hybrid films have been prepared. To fabricate UV photodetectors from the hybrid films, a thin Au layer was deposited onto the hybrid films in a vacuum evaporation method acting as contact, and interdigital electrodes were configured via a photolithography and wet etching process. For comparison, ZnO layers without the carbon nanodots have also been prepared, and photodetectors have been fabricated from the ZnO layers. The morphology of the QDs was characterized using a Philips TF-F20 transmission electron microscope operating at 200 kV. The absorption spectra of the ZnO QDs and carbon nanodots were studied in a Shimadzu UV-3101 PC scanning spectrophotometer. The photoluminescence spectra of the carbon nanodots and ZnO QDs are measured in a Shimadzu F4500 spectrometer with a Xe lamp as the excitation source. Photoresponse properties of the hybrid films were measured in a SPEX scanning monochromator employing a 150 W Xe lamp as the illumination source. The current- voltage measurement of the photodetector was measured in a Lakeshore 7707 Hall system.