Optoelectronic attenuation behavior of Al2O3/ZnO nanolaminates grown by Atomic Layer Deposition

Abstract

Zinc oxide (ZnO) and aluminum oxide (Al2O3) nanolaminates deposited in a homemade Atomic Layer Deposition (ALD) system are presented. In this work, three samples with a multi-films structure formed by four Al2O3/ZnO bi-layers of 20 nm were synthetized by thermal ALD. To analyze the optoelectronic response, the thickness of the Al2O3 was varied at 1%, 3% and 5% of the total bi-layer width for each sample. A curve of saturation was performed by means of spectroscopic ellipsometry to determine the dose time for the precursors. As a result, the synthesis of ZnO films was obtained using 50 ms for Diethylzinc dosification. To estimate the thickness of Al2O3 layers of the nanolaminates, X-ray photoelectron spectroscopy was used. To characterize the optical response of the samples, room temperature cathodoluminescence spectra were obtained from different multilayer structures. The attenuation of the luminescence was related to the integration of the aluminum oxide on the nanolaminates. As a result, a correlation between the reduction of the luminescence intensity of the multilayer and the increment of the Al2O3 layer thickness was demonstrated. The accurate control on the deposition of thin films makes this process a suitable method to be used in the optoelectronic industry as a precise coating technique with attenuation applications.