Ionic electrodeposition of II-VI and III-V compounds II. Calculated current density and stoichiometry vs. deposition potential curves for parameter values representative of CdTe and with one partial current density diffusion limited

Journal Article · Sun Dec 01 04:00:00 EST 1985 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2113693· OSTI ID:6067019

Engelken, R D; Van Doren, T P

This article presents the results of a computer simulation of the kinetic model, developed in the first part of this paper for the electrodeposition of 13-15 (III-V) and 12-16 (II-VI)(notably CdTe) compounds from solutions containing reducible ions of both deposit constituents. The simulation utilized parameter values approximating those of CdTe. The calculated graphs of current density and constituent mole fractions vs. deposition potential indicate that the potential of perfect stoichiometry (PPS), the potential at which x /sub Cd/ is identical to x /sub Te/ and x /sub CdTe/ approx. = 1, can li positive of the pure cadmium Nernst potential (E /sub Cd/ ) at the sharp positive shoulder of a nearly constant current plateau. This plateau corresponds to cadmium underpotential depositing on a nearly 1:1 basis with tellurium only because of the reduction in cadmium activity associated with compound formation. This is named conventional underpotential deposition (CUD). n-CdTe can be deposited within this plateau region, but native p-CdTe can be deposited only within a very small potential range positive of the PPS. When the cadmium and tellurium ion concentrations are of the same order of magnitude, the PPS can be shifted negative of E /sub Cd/ and onto the steep portion of the cadmium current curve. If the diffusion-limited current densities are matched so that equal molar fluxes occur at the cathode, the PPS shifts onto the diffusion-limited, nearly-constant current region negative of E /sub Cd/ so stoichiometric CdTe (MX) can be plated over a broad potential range. This is named matched diffusion-limited current (MDLC) deposition. The activity coefficient parameter, BETA, has negligible effect on the PPS during CUD, but varies the width of the plateau region. Less negative ..delta..G/sup 0/ /sub MX/ values shift the PPS negative and decrease the plateau width.

• Research Organization: Electronic/Photovoltaic Materials Research Group, Department of Engineering, Arkansas State University, State University (Jonesboro), AR
• OSTI ID: 6067019
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 132:12; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
ACTIVATION ENERGY
CADMIUM COMPOUNDS
CADMIUM TELLURIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COMPUTERIZED SIMULATION
CURRENT DENSITY
DEPOSITION
DIFFUSION
ELECTRODEPOSITION
ELECTROLYSIS
ENERGY
KINETICS
LYSIS
MATERIALS
MEASURING METHODS
N-TYPE CONDUCTORS
P-TYPE CONDUCTORS
POTENTIALS
REACTION KINETICS
SEMICONDUCTOR MATERIALS
SIMULATION
STOICHIOMETRY
SURFACE COATING
TELLURIDES
TELLURIUM COMPOUNDS