Insight into Magnesium Doping on Morphology, Optical, and Electrical Properties of Cu2O Layer Synthesized by Electrodeposition Method

Abstract

Cu₂O stands out as a promising semiconductor material for solar energy conversion, primarily due to its exceptional light-absorbing qualities and its widespread availability. However, its efficiency is somewhat hindered by its relatively low carrier mobility and a limited absorption band for carriers. The introduction of magnesium (Mg) doping into Cu₂O has emerged as a potential means to enhance its morphology, optical characteristics, and electrical properties, making it an intriguing avenue for exploration. To fabricate the Mg-doped Cu₂O layers, an electrodeposition process was employed on an Indium Tin Oxide (ITO) substrate. The resulting films were then subjected to characterization using Field Emission Scanning Electron Microscopy (FESEM), Ultraviolet-Visible Spectroscopy (UV-Vis), and HALL Effect Measurement, focusing on their morphology, optical properties, and electrical behaviors. Notably, the concentration of magnesium played a significant role in shaping the properties of the Cu₂O layer. The fabrication process extended up to a dopant concentration of 0.3 M for both undoped Cu₂O and Mg-doped Cu₂O layers, leading to morphological alterations. Specifically, the grain size increased with varying dopant concentrations, but it became smaller and more compact after doping with 0.3 M Mg. The average absorbance of visible light for both undoped and Mg-doped Cu₂O layers fell within the range of 1~2 au. Intriguingly, a doping level of 0.3 M Mg led to the simultaneous achievement of high carrier mobility (29.98 cm²/Vs), low bulk carrier concentration (2.3.928 x 10²¹ cm^-3), and high resistivity (5.3 x 10^-5 Ω cm) in the Cu₂O material. Additionally, Cu₂O/ITO thin films exhibiting rectifying characteristics were successfully fabricated, confirming the semiconductor nature of the deposited p-type Cu₂O layer. The primary objective of this study was to synthesize Cu₂O layers doped with varying concentrations of Mg and thoroughly characterize their morphology, optical attributes, and electrical behaviors through the electrodeposition method. The study findings and implications were extensively discussed.