The reaction rates and thermodynamic parameters governing cation exchange between molecular Cd2+ precursors and ZnTe nanorods is mapped out in detail to provide an all inclusive rubric for tuning the rate and extent of cation exchange in this system – allowing for band gap tunability over a 1 eV range. Evaluation of cation exchange as a function of concentration, temperature, and time supports a mechanism involving initial, rapid Cd2+ adsorption followed by a rate determining cation exchange step with a measured activation energy of 24 kJ/mol. As long as there is sufficient cadmium to occupy the available surface sites, the solution concentration of cadmium has little influence on the rate of cation exchange, allowing the system to be modeled using pseudo-first order kinetics, with observed rates ranging from 0.03x10-3 s-1 at 20 °C to 2.8x10-3 s-1 at 240 °C.

Quantifying cation exchange of Cd2+ in ZnTe: A challenge for accessing type II heterostructures

253rd National Meeting (2017)

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