Doping and irradiation effects on the optical band gap of potassium tetrachlorozincate single crystals

Optical transmission and reflection measurements for crystals of potassium tetrachlorozincate (KZC) doped with Mn2+ or Ni2+ in different concentrations and irradiated with different gamma-doses have been carried out along the three crystallographic axes. The results were analyzed to determine the absorption coefficient (alpha), type of optical transition and the optical energy gap (E-g). Different absorption bands along the three axes have been observed. Doping with Mn2+ or Ni2+ affected the intensity and position of these bands. Irradiation by gamma either created or inhibited some of these bands. The nature of the transition involved was found to be the indirect allowed one. Doping with Mn2+ or Ni2+ up to 0.41 wt% and irradiating with gamma-doses up to 150 kGy did not change the type of transition. The optical energy gap decreased considerably after doping and irradiating KZC.