Formation of acceptor centers in CdHgTe as a result of water and heat treatments

Influence storage and boiling in deionized water and heat treatments of epitaxial films Cd$_{x}$Hg$_{1-x}$Te on the Hall and ellipsometric parametres is investigated. Water treatment reduces refractive index of native Cd$_{x}$Hg$_{1-x}$Te oxide from 2.1 to 1.2–1.4. It means that matter with a lower refractive index, such as water, is introduced in the oxide. Boiling in water leads to formation of acceptors in Cd$_{x}$Hg$_{1-x}$Te with concentrations up to 10$^{19}$ cm$^{-3}$. Change of medium's pH from alkaline to the acidic decreases the speed of acceptors formation. Heat treatments after storage in water also leads to formation of acceptors. The conclusion is made, that water medium or water absorbed by native oxide layer leads to formation of acceptors in Cd$_{x}$Hg$_{1-x}$Te. Concentration of acceptors grows with temperature of treatments and quantity of accessible water.