Semiconducting and transport properties of mono- and polycrystalline nickel oxide

On the basis of high-temperature studies of electrical conductivity of poly- and monocrystalline nickel oxide and making use of the results of studies on chemical diffusion coefficients obtained by several authors and in the present work, the structure of point defects in nickel oxide has been considered. It has been shown that in the temperature range 900 to 1300° C and at the oxygen pressure from 10^–4 to 1 atm there occur in nickel oxide singly- and doubly-ionized cationic vacancies in comparable quantities.Assuming such to be the model of defect structure in Ni_1–yO, the equilibrium concentration of cationic vacancies as a function of temperature has been calculated for the oxygen pressure of 1 atm. It has been shown that the results obtained are in good agreement with the results of direct determinations of concentration of cationic vacancies in NiO.