| 초록 |
In this work, Ag-Mo (10 nm) ultra thin films in which the molybdenum (Mo) composition is 1 at.% were deposited on crown-sodalime glass by D.C. magnetron sputtering with Ag-Mo mosaic target. The films were characterized by using Atomic force microscopy, Field-emission scanning electron microscopy, Ultraviolet-Visible-Near infrared spectrophotometer, and a four point probe method. Ag-Mo films showed very low root mean square (RMS) surface roughness, very low sheet resistance (R□) and also the transmittance in the visible region enhanced greatly by 11% than that of silver (Ag) films at same thickness and deposition conditions. Microstructure of the films revealed a smooth surface which would be due to the presence of Mo at the grain boundary sites of Ag. From the atomic force microscopy (AFM) results, the average crystal diameter of the Ag-Mo thin films is 3.8 nm and peak-to-valley is 13 nm. The average crystal diameter and peak-to-valley in Ag films is 5.3 nm and 14.1 nm, respectively. The RMS roughness of Ag-Mo and pure Ag thin films is 1.7 and 4.9 nm respectively. From the acquired results, it is obvious that the average crystal diameter is 1.4 times and RMS roughness is 2.9 times lower in Ag-Mo films than that of Ag films, because of the Mo addition. The transmittance of the Ag-Mo and Ag films is 59% and 48% respectively at 550 nm. In the near infrared range of the electromagnetic spectrum, the Ag-Mo films showed 25% transmittance, which is 2% lower than the Ag thin films. The sheet resistance of the Ag-Mo and Ag films is 1.6 and 21.6 Ω/□, respectively. Such a high conductivity is obtained because of the extremely smooth surface of the films. In fact, it is well known that the rough surfaces are effectively lost their electrical conductivity because of the scattering of electrons. Ag films showed the emissivity 0.25. The emissivity of the Ag-Mo films is 0.02, which is 12.5 times lower than Ag films. Such an extraordinary result without any seed/inter layer has rarely been reported. The results obviously suggest that the Ag-Mo (10 nm) ultra thin films can be a promising structure for low emissivity (low-e) systems in the energy saving applications and architectural windows. |
