Study on the durability against heat in ITO/Ag‐alloy/ITO transparent conductive multilayer system

Abstract

We studied the effects of added metallic elements in Ag-alloy layers of indium-tin-oxide (ITO)/Ag-alloy/ITO transparent conductive multilayer system on the durability against heat. When Ag film was heat treated, agglomeration occurred due to the surface diffusion of the Ag atoms. This caused an increase in the sheet resistance and a decrease in the transmittance. Added metallic elements such as Au, Pd, and Cu in Ag-alloy layers increased the onset temperature and activation energy for agglomeration. These added metallic elements also decreased the surface energy of the Ag film. The durability against heat was improved by adding metallic elements to the Ag film of the ITO/Ag/ITO multilayer system. Cu atoms, especially, diffused out to the surface of the Ag film hindered the surface diffusion of the Ag atoms, resulting the improvement of thermal stability of the Ag film. The figure of merit (FOM, T 10 /R & ) of ITO/Ag/ITO multilayer decreased to 1/15 of its initial value after heat treatment at 450 8C for 6 h, whereas it decreased to 1/3 of its initial value when Pd and Cu were added to Ag film.

Enhanced transmittance of ITO/Ag(Cr)/ITO (IAI) multi-layered thin films by high temperature annealing

“…The highest achieved transmittance of the multilayer film recorded at 500 1C is $ 96% (wavelength 550 nm) with an electrical resistivity of 7 Â 10 -5 Ω cm (R sh ¼10 Ω/□). Although, the lower sheet resistance can be achieved by increasing the thickness of metal layer but that will reduce the transmittance of multilayer film [20][21][22][23]. It is known that, the high temperature heat treatment was effective to reduce the defects which are responsible for light scattering that lead to improvement in the transmittance of the film [27,28].…”

“…Sheet resistance (R sh ) o10 Ω/□ with transmittance $ 90% was achieved by incorporating a thicker metal film [20][21][22][23] and post deposition annealing [10,20]. Also, it has been suggested that, the high transmittance 490 is necessary with R sh r10 Ω/□ for the reduction of optical and power losses in various displays and solar cell devices [24].…”

“…Hence, durability of multilayer electrode against heat treatment is necessary to improve multilayer properties. It has been also reported that, the usage of Ag-alloys with a suitable elements like Au, Pd, Cu, Mo, Cr, etc., are favorable to improve Ag layer stability against heat treatment [11,13,[18][19][20]25,26]. Thus, in this study, ITO and Ag(Cr) alloy thin films based ITO/Ag(Cr)/ITO (IAI) triple layer structure has been introduced for the transparent conducting electrode (TCE) application.…”

Highly transparent conductive ITO/Ag/ITO trilayer films deposited by RF sputtering at room temperature

“…23 In this case, Ag, Cu, Au, Al and their alloys were often deposited between two metal oxide layers to form a sandwichstructure TCF stack. 22 A large number of transparent conductive oxides (TCOs), e.g., ZnO, 23,24 AZO, 25 MgZnO, 26 FTO, 27 WO 3 , 28 ITO, 29 etc., were employed to improve the performance of trilayer TCFs.…”

“…The electric and optical behaviors of IAI films strongly [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] have led to significant improvement on the performance of IAI trilayer electrodes.…”