Modification of diluted magnetic semiconductor Cd_0.9Mn_0.1Te crystal through annealing

The point defect density of Cd_0.9Mn_0.1Te crystal was calculated approximately by the quasi-chemical theory, and obtained the optimum annealing condition in which the deviation from stoichiometry of the crystal is the least. The two-temperature-zone-annealing experiment was done under this condition and the effects of annealing on the properties of Cd_0.9Mn_0.9Te were analyzed in detail. The results show that when the as-grown crystal was annealed for 140 h in Cd atmosphere at 973 K, the full-width-at-half-maximum (FWHM) of X-ray rocking curve was reduced from 168.8″ to 108″, the IR transmission was improved from 48% to 64%, which is close to the theoretical value. Meanwhile the resistivity is increased from 2.643×10⁵ Ω·cm to 4.49×10⁶ Ω·cm. The results prove that the annealing treatment of the as-grown Cd_0.9Mn_0.1Te crystal can improve the crystal quality, compensate Cd vacancy, and homogenise the crystal composition close to the theoretical stoichiometry.