Comparison of ZnTe bulk crystals grown by the temperature gradient solvent method using elemental and compound materials

Crystal boules of ZnTe up to 50 mm in length and 30 mm in diameter were grown by the temperature gradient solvent method. We experimentally confirmed that ZnTe crystal grown using elemental raw materials is superior for THz application, owning to the slight free-carrier absorption and secondary phase associated defects scattering, which is consistent with its higher resistivity and crystallization. However, abundant Te-SP particles enriched at the subgrain boundaries are observed in ZnTe crystals grown by compound powders. Moreover, relative lower resistivity is recognized by fitting the I-V curve, which is mainly contributed by the oxygen.