Antistructural disordering in GeTe

An attempt was made to establish the type and number of defects in GeTe versus the degree of deviation from stoichiometry. Since various structural defects produce different effects upon intensity of diffracted emission, the structural defects in an actual material could be observed by comparing the experimental and theoretical intensities of diffraction lines computed for varions structural defect models. Experimental intensities of investigated GeTe compositions disagree with theoretical lines. The difference between Isub(theor) and Isup(exp) for investigated alloys increases with increasing excess of Te which may be explained by change of structural defects in GeTe. The type of structural defects may be different. However defects could not be identified on the basis of X-ray data alone because different defects may influence the X-ray line intensities. Therefor physical properties were used for investigating structural defects of GeTe. Roentgenographic analysis, density and Hall concentration of current carriers measurements showed that GeTe has complex defect structure containing vacancies and the antistructural disorder defects. Concentration of the latter is a function of composition and increases with deviation from stoichiometry