2026-06-29T07:33:24Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/136262023-08-28T15:01:52Zcom_20.500.14352_14col_20.500.14352_15

Use of light for the electrochemical deposition of Bi on n-GaAs substrates Prados Díaz, Alicia Ranchal Sánchez, Rocío 538.9 Electrolyte junctions Current transport Steady-state Surface Nucleation Mechanism Kinetics Electrodeposition Growth Evolution Bismuth n-GaAs Electroless Thermionic emission Física de materiales Física del estado sólido 2211 Física del Estado Sólido ©2019 Elsevier Ltd. All rights reserved This work has been financially supported through projects MAT2015-66888-C3-3-R (MINECO/FEDER) and RTI2018-097895-B-C43 of the Spanish Ministry of Economy and Competitiveness. We would like to acknowledge the postdoctoral fellowship granted by Consejeria de Educacion, Juventud y Deporte de la Comunidad de Madrid and the European Social Fund (grant PEJD-2016/IND-2233 of the YEI program). We also acknowledge the use of facilities of Instituto de Sistemas Optoelectronicos y Microtecnologia (ISOM). In this work, we have explored the possibility of using light to remove the adsorbed hydrogen layer that blocks the GaAs surface when electrodepositing Bi thin films on lower-doped n-GaAs(111)B substrates. A light pulse of a few seconds applied under open-circuit (zero-current) conditions before starting the electrodepositionof Bi in darkness has a small effect on the structural, morphological and interfacial electrical properties of the Bi film in comparison to layers deposited without the use of light. The potentiostatic curves recorded during the Bi nucleation show that the light pulse does not remove the adsorbed hydrogen layer but modifies the n-GaAs surface, inhibiting the reduction of Bi(III) ions. The atomic force microscopy analysis of the n-GaAs surface corroborates that the light degrades the surface by inducing photo-oxidation reactions, phenomenon that is correlated to the photocorrosion of the substrate. To maintain the electrical neutrality during photocorrosion, proton reduction and electroless deposition of Bi occur in parallel to the photo-oxidations. The simultaneity of these processes and the inhibition of Bi(III) ions to get reduced on those areas of the n-GaAs surface chemically altered enables the electroless deposition of unconnected Bi flakes with morphological, structural and interfacial electrical properties close to the state of the art of Bi thin films. Only the out of plane crystal quality of the Bi flakes show a small detriment whereas the Schottky barrier height slightly increases. Ministerio de Economía y Competitividad (MINECO)/FEDER Ministerio de Economía y Competitividad (MINECO) Comunidad de Madrid/YEI Depto. de Física de Materiales Fac. de Ciencias Físicas TRUE pub 2023-06-17T13:29:53Z 2023-06-17T13:29:53Z 2019-09-01 journal article https://hdl.handle.net/20.500.14352/13626 0013-4686 10.1016/j.electacta.2019.05.085 eng MAT2015-66888-C3-3-R RTI2018-097895-B-C43 PEJD-2016/IND-2233 Atribución-NoComercial-SinDerivadas 3.0 España https://creativecommons.org/licenses/by-nc-nd/3.0/es/ open access application/pdf Pergamon - Elsevier Science