Electrical and Optical Properties of Bulk ZnO Single Crystal Grown by Flux Bridgman Method

Zinc oxide (ZnO) single crystals are grown by the modified vertical Bridgman method using a PbF₂ flux. The maximum size of the as-grown ZnO crystal is about Ф25 mm×5 mm. The transmittance of the as-grown ZnO crystal is more than 70% in the range of 600--800 nm and the optical band gap is estimated to be 3.21 eV. The photoluminescence spectrum indicates that the as-grown ZnO crystal has a very low concentration of native defects and is much closed to its stoichiometry. The electrical measurement exhibits that the ZnO crystal has low electrical resistivity of 0.02394Ωcm^-1 and a high carrier concentration of 2.10×10¹⁸ cm^-3.