The diffusion of Cl into CdTe

Abstract

Results on the diffusion of Cl into CdTe are described. Diffusion anneals were carried out at selected temperatures in the range between 200 degrees C and 700 degrees C in evacuated SiO2 ampoules using a diffusion source of CdCl2 under saturated vapour pressure conditions. The concentration profiles were measured using a radiotracer sectioning technique. The profiles were found to be composed of four parts, to which a computer package consisting of the sum of four complementary error functions (erfc) gave satisfactory fits to the data. The fastest-diffusing component gave values of the diffusivity that agreed with previously published results. Proposals explaining how this type of diffusion may occur are given.

Electrical activity of iodine-diffused CdTe

“…2 . It was assumed that such a profile was due to chlorine and the result is in good agreement with data reported by Jones et al 7 for the diffusion of chlorine in CdTe.…”

“…3 The projected room temperature diffusivity for the fastest part of the chlorine diffusion profiles (6 × 10 −25 cm 2 s −1 ) 7 was much lower than the corresponding one for iodine. 4 More recently, the diffusion of bromine into CdTe has been studied 8 and the concentration profiles which were measured using SIMS gave four-component profiles, yielding values of diffusivities and activation energies similar to those for the diffusion of iodine into CdTe.…”

“…Chlorine diffusion into CdTe has been studied by Shaw and Watson 6 and, more recently, Jones et al 7 In both cases complex profiles were reported, but recent advances in the sectioning technique have allowed a more elaborate analysis of the profiles to be reported in the latter publication, which could be fitted empirically by a function composed of the sum of four complementary error functions similar to the ones obtained for the diffusion of iodine into CdTe. 3 The projected room temperature diffusivity for the fastest part of the chlorine diffusion profiles (6 × 10 −25 cm 2 s −1 ) 7 was much lower than the corresponding one for iodine.…”

Morphological effects and the diffusion of iodine in CdTe

“…dislocations or subgrain boundaries) [13] or chemical disequilibrium. The occurrence of four component profiles, which have been observed for the diffusion of iodine and chlorine into CdTe [4,5,6,14] together with high surface concentrations of up to 1023 cm -3 is a rather unique feature, as no similar observations have been reported previously and are probably as much a consequence of the high-resolution sectioning technique used in this work as they are a feature of the system under investigation. An attempt is made in the following paragraphs to propose a model to explain such profiles using the information reported here.…”

Empirical Correlations Between the Arrhenius’ Parameters of Impurities’ Diffusion Coefficients in CdTe Crystals

“…Thus, according to, [56][57][58][59] the profiles of halogens (Cl, Br, and I) comprise four parts that can be treated as the sum of four complementary error functions. Assuming that a change in the diffusivity mechanism is accompanied with the CEF correlation between pre-factors D 0 and DE a, all the Arrhenius' parameters were used for the graphical analysis (Fig.…”