Formation of Acceptor Centers in CdHgTe as a Result of Water and Heat Treatments

The influence of deionized water and heat treatments of samples of epitaxial Cd x Hg 1 − x Te films on the Hall and ellipsometric parameters is investigated. Water treatment reduces the refractive index of natural Cd x Hg 1 − x Te oxide from 2.1 to 1.2–1.4. This means that a substance with a low refractive index, such as water, is introduced into the oxide. Boiling in water leads to the formation of acceptors with concentrations of up to 10 19 cm –3 in Cd x Hg 1 − x Te. Changing the acidity of the medium from alkaline to acidic decelerates the formation of acceptors. Heat treatments after holding in water also lead to the formation of acceptors. It is concluded that an aqueous medium, including water that is absorbed by the natural oxide layer, leads to the formation of acceptors in Cd x Hg 1 − x Te. The acceptor concentration increases with the temperature of treatments and the amount of available water.