Precise compositional and trace-elemental analysis by chemical methods in compound semiconductors

Off stoichiometry determination in cadmium telluride crystals

“…The techniques that, in principle, should give the best precision (0.01-0.001%) for the determination of the stoichiometry in semiconductor materials are titration and coulometry [6], but practically, in the case of cadmium telluride, a precision of respectively 0.06-0.2% [8] and 0.1% [7] was demonstrated.…”

“…However, previously reported methods for the characterisation of the stoichiometry show poor precision. The sensitivity, when using X-rays fluorescence and energy dispersive X-ray analysis (EDS), is limited to 0.1% [6], insufficient for the stoichiometry evaluation of crystals grown under different conditions [7].…”

Off-stoichiometry determination of II–VI bulk crystals

“…(3) and (4) by varying the pressure around the experimental value. This is an important result, taking into account that the sensitivity of the technique is practically only limited by the precision in the knowledge of the compound existence region (typically in the 50.001-50.0001 mol% range [4,6] sensitivity that is two to three orders of magnitude better than the previously reported methods [1][2][3]. …”

“…However, the available characterization techniques for the determination of the deviation from stoichiometry are usually not accurate enough. For example, in the case of II-VI materials, the previously reported techniques (X-ray fluorescence, titration and coulometry) can hardly detect deviations o0.1 mol% [1][2][3]. This sensitivity is clearly unsatisfactory, because the maximum width of the existence region for II-VI compounds is in the 0.01 mol% range [4][5][6].…”

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

“…In the past, different methods have been proposed for the determination of the stoichiometry of CdTe crystals, such as X-ray fluorescence and energy-dispersive X-ray analysis (EDS) [3], titration [6] and coulometry [7]. However, the precision of these techniques never reached an experimental error lower than 0.06 mol%.…”