Study on electrodeposition of gallium-selenium binary alloy films from Deep Eutectic Solvent

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2024-08, Vol.967, p.118472, Article 118472
• Main Authors: Wu, Qihu, Wang, Wenchang, Huang, Jiacheng, Ming, Zhiyao, Wu, Minxian, Wang, Pengju, Mitsuzaki, Naotoshi, Chen, Zhidong
• Format: Article
• Language: English
• Subjects: Co-deposition; Deep Eutectic Solvent; Electrodeposition; Ga-Se alloy; Photoelectric property
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2024.118472

•By employing a eutectic solvent of choline chloride-ethylene glycol as the electrolyte, issues related to hydrogen evolution during Ga3+ deposition and electrolyte instability are circumvented. Additionally, the eutectic solvent narrows the reduction potential difference between Ga3+ and Se4+, facilitating the co-deposition of Ga and Se.•The results indicated that the morphology and composition of Ga-Se alloy coatings can be controlled by adjusting the deposition potential.•By the electrodeposition method, a Ga-Se alloy coating was obtained from a eutectic solvent of choline chloride-ethylene glycol. After annealing treatment, the alloy coating exhibited good photoelectrical properties with a photocurrent response of 0.014 mA/cm2. Ga-Se alloy coatings were successfully electrodeposited at different deposition potentials from Deep Eutectic Solvent (choline chloride-ethylene glycol). The co-deposition mechanism of Ga and Se was investigated through cyclic voltammetry (CV) and chronoamperometry (CA). The results indicate that the co-deposition of Ga and Se occurs through an induced co-deposition mechanism, with Se deposition taking place initially, followed by the induced deposition of Ga. Furthermore, the Ga-Se co-deposition process was analyzed with the Scharifker-Hills model. The research results indicate that with the negative shift of the deposition potential, the Ga-Se co-deposition process gradually transitions from diffusion-controlled three-dimensional progressive nucleation and growth to three-dimensional instantaneous nucleation and growth. Characterization of the surface morphology and composition of the obtained coatings at different potentials was analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results reveal that with the negative shift of the deposition potential, the morphology of the coating transforms from spherical to granular, and as the deposition potential continues to decrease, the granules further refine. Simultaneously, with the negative shift of the deposition potential, the relative content of Ga in the coating increases, while the relative content of Se decreases. The Ga-Se alloy coatings before and after annealing were characterized by X-ray diffraction spectroscopy (XRD). The results indicate that, after annealing, the coating exhibits the phase of GaSe. Besides, the optical and electrical properties of the annealed Ga-Se alloy coating were investigated by UV–visible spectrosco