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

Off-stoichiometry determination of II–VI bulk crystals

“…The sensitivity of the technique changes by changing the ratio between the mass of the sample and the free volume of the ampoule [7]. In fact, the same amount of excess moles gives rise to a larger pressure as the volume of the system is decreased, or, in other words, a larger excess gives rise to a larger pressure in a constant volume.…”

“…The determination of the off-stoichiometry in an anionrich binary compound AB basically requires the solution of the coupled equations [7,13]:…”

“…Some of the authors have recently developed a method to determine the off-stoichiometry of CdTe samples, with sensitivity in the 10 À4 mol% range, by using an accurate analysis of the vapor partial pressures in equilibrium with the samples at high temperatures [7]. The partial vapor pressures can be determined by means of their optical absorption at the wavelengths of a HeCd laser source.…”

Boron oxide fully encapsulated CdZnTe crystals grown by the vertical Bridgman technique

“…Both the methods for the partial pressure measurements and for the determination of the sample composition by means of partial pressure data were described elsewhere [16,17]. Fig.…”

“…At low temperatures, the pressure follows basically the Te-liquid pressure curve, then, at a temperature T s , the slope of the curve clearly changes and the system enters a two-phase region. At the temperature T s , the solubility of tellurium in CZT is known [18], and the sample composition at room temperature can be determined [17]. The sample composition is found to be X Te ¼ 50:0032 mol%.…”