Aging and degradation of transparent copper iodide thin film electrodes for functional electronic devices

Abstract

Transparent CuJ copper iodide thin-film electrodes are widely used in various optoelectronic devices, such as solar cells, electroluminescent displays, touch screens, multifunctional photoconverters, etc. Their advantages are high transparency, because CuJ absorbs light in a limited range of wavelengths, which allows them to transmit visible light, making them ideal for transparent devices, low cost, because copper iodide is an inexpensive material, making it economically viable for mass production, simplicity fabrication, as CuJ can be easily deposited on various substrates using simple film deposition techniques such as vacuum deposition and magnetron sputtering. However, transparent CuJ type thin-film electrodes are subject to aging and degradation, which can reduce their performance and service life. The main factors affecting the aging and degradation of CuJ are the processes of oxidation, diffusion, degradation under the influence of light, and humidity. Despite numerous studies in the direction of obtaining high-quality thin films of copper iodide, today there is a need for a detailed study of the processes of their aging and degradation of properties. Therefore, in this article, we investigated the degradation processes of transparent upper copper iodide electrodes of thin-film multicomponent semiconductor heterostructures. This article shows the features of the use of film copper iodide in multilayer thin-film semiconductor structures. The influence of atmospheric conditions and lighting on the values of the rates of degradation of electrical resistance of copper iodide in semiconductor thin-film structures was studied. It has been found that atmospheric exposure to oxygen, moisture and other factors increases the electrical resistance of the copper iodide top electrode, and the use of Elastosil sealant does not lead to appreciable improvement. Heterostructures in vacuum are minimally affected by external factors, and therefore a significant increase in their CuJ upper electrode resistance values indicates the predominant role of aging of copper iodide films, which is not related to atmospheric conditions. It was established that natural sunlight significantly increases the degradation of copper iodide films, which should be taken into account when forming and using the corresponding thin film structures.