In-depth optical and structural study of silver-based low-emissivity multilayer coatings for energy-saving applications

Abstract

Low-emissivity coatings on glass, which provide highly efficient heat isolation, are nowadays extensively used in windows in offices and residential buildings for the purpose of saving energy in air conditioning. In this paper, multilayer low-emissivity coatings with the structure glass/SnO 2 /Ni-Cr/Ag/Ni-Cr/SnO 2 were deposited onto large glass substrates in an industrial sputtering system. The extremely low thickness of the layers which compose such structures, as well as the large substrate area, causes the structure and impurity content of the films and interfaces to play an important role in providing efficient energy-saving performance as well as high optical transmittance. Thus, in-depth characterization was performed by spectroscopic ellipsometry, Rutherford backscattering spectroscopy and Auger electron spectroscopy. The use of these characterization techniques provides the great advantage of allowing the investigation of the whole multilayer system, including the interfaces. However, the properties of the individual layers (density, composition and optical behaviour) were also determined independently and compared to the values of corresponding bulk materials. Special attention is devoted to inter-diffusion of species.

Diamond-like carbon based low-emissive coatings

“…Moreover, potential changes in the microstructure of DLC when deposited on top of or underneath Ag need to be examined. These types of investigations were the key to improve the SnO 2 based low-E coatings as several studies have thoroughly investigated the growth and interface of Ag on SnO 2 and Ag on NiCr [20,[30][31][32][33][34].…”

Optical membrane technology for deep space optical communications filters

“…A sensitive Anritsu optical power meter was placed on an optical rail, and allowed to travel perpendicularly to the transmitted beam, as shown in the figure. Positions corresponding to angles of 0,3, 5,7,9,11,13 and 15 degrees were marked off on the rail.…”

“…This filter uses a 38 nm thick layer of silver [7] in the middle of 16 alternating dielectric layers of SiO 2 and Ta 2 O 5 on the front of the membrane, along with 13 alternating dielectric layers on the back. The total layer thickness (both front and back sides) is under 5 microns, which is reportedly compatible with deposition and good The angular performance of this filter transmission at 1064 nm is also very good, as shown in Figure 7, exhibiting little if any rolloff in transmission at angles beyond 5 degrees.…”

Ag/M‐seed/AZO/glass structures for low‐E glass: Effects of metal seeds

“…A recent work has mentioned sputtered Ag films on ZnO and Zn 2 SnO 4 on glass and emphasized ZnO is superior because it promotes (111) preferred orientation of the Ag film . Furthermore studies showed that the formation of metal seed layers with subnanometer thickness between the Ag and dielectric metal‐oxide layer would be effective to overcome island silver growing on the glass substrates . These seed layers are used to protect silver against oxidation and it also improve the glass performance.…”