Optical Properties and Stability of Copper Thin Films for Transparent Thermal Heat Reflectors

Iulian Pana,Anca C Parau,Catalin Vitelaru,Lidia R Constantin,Mihaela Dinu,Adrian E Kiss

doi:10.3390/met12020262

Iulian Pana, Anca C Parau + Show 4 more

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https://doi.org/10.3390/met12020262

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Abstract

The use of thin metallic layers at the thickness limit where transparency or spectral selectivity are achieved is gaining increased interest. The use of cheap and abundant materials is desirable in the attempt to avoid environment or economical costs. The use of Cu as a replacement for Ag as a heat reflector is one of the solutions that can be employed. The stability over time is a known issue, copper being prone to atmospheric oxidation and degradation. In this contribution, the stability of Cu obtained by magnetron sputtering is investigated, using both DC and HiPIMS processes for obtaining the Cu thin films. The bias voltage is used to obtain thin films with different properties, their time stability being investigated through the variation of spectrophotometric curves. The best performing thin films are evaluated in theoretical heat reflector structures, using SiNx of different qualities as dielectric layers to form the dielectric/metal/dielectric structure.

Highlights

M.; Kiss, A.E.; Constantin, L.R.; In the past few decades, there has been an increasing interest in decreasing the overall energy consumption and implicitly decreasing CO2 emission into the atmosphere [1]
The best performing thin films are evaluated in theoretical heat reflector structures, using SiNx of different qualities as dielectric layers to form the dielectric/metal/dielectric structure
We propose the composition changes, adding a supplementary degree of freedom when designing use a of its tunable optical properties as its composition changes, adding a supplementary degree multilayer structure with prefigured optical properties

Summary

Introduction

M.; Kiss, A.E.; Constantin, L.R.; In the past few decades, there has been an increasing interest in decreasing the overall energy consumption and implicitly decreasing CO2 emission into the atmosphere [1]. The sputtering under high power mode allows obtaining higher ionization rates and corresponding higher ion fluxes to the substrate [9], the use of proper biasing to the substrate enabling the energy control and impinging ion flux [7] This leads to corresponding changes of the film properties with increasing ion flux, such as increased grain size and crystallinity, decreased roughness, increased stress, decreased resistivity [7], higher hardness and Young modulus, and lower friction coefficient [10]. The using in based Low-E structures has already been proved and is implemented at the industrial a SiNsilver x layer as dielectric are its good optical properties, chemical stability, and scratch scale [17,18].

Materials and Methods

Results and Discussion

Copper Metallic Layers

Figures and

Conclusions