Morphological and quality assessments of unary and binary base immersion-fabricated cupric/cuprous oxide nanoflake-coated copper

Abstract

Mass production practicable fabrication techniques for wide-application-ranged cupric oxide (CuO) or cuprous oxide (Cu₂O) nanostructures are crucial in its research-to-technology thrust. Films of CuO/Cu₂O were grown onto copper as coating via a 16-day unary or binary immersion to solutions of barium hydroxide (Ba(OH)₂) and/or potassium hydroxide (KOH) with varying concentration proportions. Physical inspection and Raman spectroscopy confirms the identity of the grown films to be CuO for all specimens under study except for the copper foil immersed in unary KOH wherein CuO coexists with Cu₂O. Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) reveals the nanoflake morphology of the oxide layers with minimal traces of impurities (maximum impurity: 4.17 At.%) and the abundance of oxygen atoms (41.14–55.68 At.%) among the samples. Copper-to-oxygen ratio of the samples ranged from 0.7 to 1.41. Moreover, analysis of variance (ANOVA) reveals the significant differences of the film and flake thicknesses among the specimens under study. The average nanoflake thickness increases as Ba(OH)₂ amount is decreased as opposed to KOH up to the binary immersed sample with equal component proportions (maximum average: 71.7 nm), then decreases as KOH concentration is increased in expense of Ba(OH)₂ (minimum average: 29.5 nm). The average film thickness is highest for the 75-Ba(OH)₂:25-KOH immersed foil and a decreasing trend is apparent as KOH is further increased at the expense of Ba(OH)₂. Preliminary assessments may qualify the fabricated oxide nanoflakes on copper for potential applications.