Solid–vapor equilibrium in quasi‐binary CdTe—ZnTe

Abstract

Total vapor pressure measurement and Knudsen cell mass spectrometry have been applied to study sublimation processes in the quasi-binary system CdTe-ZnTe at temperatures 780 K -1350 K. This system was shown to correspond to the vapor pressure minimum in the pressure-temperature-composition (P-T-X) phase diagram of the ternary system Cd-Zn-Te. The shape of the solidus and vaporus surfaces was traced via experimental isothermal and isobaric sections of the P min area up to the near-melting region. Relationship between the composition of the crystal, vapor pressure and composition of the vapor was determined in the whole concentration range. At temperatures above 780 K CdTe-ZnTe was found to be a continuous solid solution with incongruent sublimation, whereas at T = 780 K a tendency to phase separation was observed. Dedicated to Professor K. W. Benz on the occasion of his 65th birthday.

Vapor pressure scanning of non-stoichiometry in Cd0.9Zn0.1Te1±δ and Cd0.85Zn0.15Te1±δ

“…This mode of sublimation has been observed experimentally in the mass spectrometric investigation of Cd 1Àx Zn x Te and discussed in detail in Refs. [15,16].…”

“…Unfortunately, for Cd 0.9 Zn 0.1 Te 17d and Cd 0.85 Zn 0.15 Te 17d strict calculation of dX S is impossible because the quantitative contribution of the ideal solution model approximation into dX S is unknown. Nevertheless, an attempt was made to assess this contribution by repeating the whole set of calculations with CdTe and ZnTe activities in Cd 1Àx Zn x Te 17d taken from the mass spectrometric experiment [15,16] rather from the ideal solution approximation. It turned out that the compositions of the solid obtained in these two models were the same to within 10 À5 -10 À6 at%, which is 1 to 2 orders of magnitude less than dX S resulting from the experimental errors for CdTe [7,8].…”

A method for an accurate determination of stoichiometric deviations in CdTe and CdZnTe bulk crystals

“…[14,15] the ratio between the Cd and Zn vapors n Cd =n Zn in equilibrium with Cd ð1ÀxÞ Zn x Te crystals is much larger than the moles ratio in the solid ð1 À xÞ=x: In particular, in the case of the technologically important cases (x ¼ 4; 10; 20%), n Zn is negligible with respect to n Cd ; taking into account the typical experimental errors in the determination of pressures. Thus, by solving Eqs.…”

P–T–X phase equilibrium and vapor pressure scanning of non-stoichiometry in the Cd–Zn–Te system

“…More recently, sub-solidus in CdTeeZnTe was studied in Ref. [58] in a wide temperature range, from 500 C to near-melting (1075 C), by vapor pressure measurements and Knudsen cell mass spectrometry.…”