Investigation on p-type lithium niobate crystals

Till now it is difficult to obtain a p-type lithium niobate crystal. Here the carrier types in various doped and oxidized LiNbO3 crystals have been investigated by holographic technique. The experimental results show tetravalent ions (Zr4+ and Hf4+) with doping concentrations just above optical damage resistant thresholds is helpful to increase the concentration of holes. And 3.0 mol% ZrO2 doped LiNbO3 can be used as a p-type crystal. The dominant carrier of iron doped LiNbO3 crystal can be changed to holes when treated by thermo-electric oxidization. Then the possible mechanism on how to obtain a p-type LiNbO3 was discussed.