Abstrakt
The chemical diffusion coefficient (D) over tilde in chlorine-doped CdTe with Cl concentration [Cl] approximate to 4.3 x 10(16) cm(-3) was determined by means of the high-temperature in-situ measurement of the relaxation of electrical conductivity after step-like changes of ambient Cd pressure for temperatures 600 degrees C, 700 degrees C and 800 degrees C. Weak dependence of (D) over tilde on the ambient Cd pressure was found.
Both (D) over tilde and equilibrium conductivity for different Cl doping were calculated based on the defect model in which monovalent chlorine donors (Cl-Te) are compensated by divalent acceptors Cd vacancies (V-Cd) and monovalent acceptor-like complexes (Cl-Te V-Cd). It was shown that experimental (D) over tilde can fit well for [Cl] = 4 x 10(16) cm(-3) assuming different diffusion coefficients for singly and doubly charged V-Cd.
The temperature dependence of (D) over tilde in the temperature interval 600-800 degrees C near Cd saturation was properly approximated by (D) over tilde (cm(2) s(-1)) = 68 exp(- 1.38 eV/k(B)T). Linear dependence of the pre-exponential term D-0 on activation energy E-A known as a Meyer-Neldel rule (MNR) was discussed in detail and its limited validity was proven based on experimental data and numerical simulations.
It was shown that the standard MNR may be conveniently extended to a "triangle Meyer-Neldel rule", which conforms with theory and relevant experiment. (C) 2019 Published by Elsevier B.V.