Study Of The Growth And Properties Of New Doped TGS Crystal SERI

Ferroelectric triglycine sulfate (TGS) crystals are the most widely used material as pyroelectric infrared detectors, thermal imaging and other infrared sensing applications because of their interesting merits, such as high pyroelectric coefficient, low dielectric constant, sensitivity in wavelength ranging from ultra violet to far infrared at room temperature, large crystal size and so on. However, the tendency of the crystals to depolarize with time is a serious drawback which can limit their applications. How to improve the pyroelectric properties and minimize the depolarization of the crystal is an important study at present.The eighteen kinds of single crystals of triglycine sulfate with single dopant and two dopants have been grown from aqueous solution by slow cooling method. The growth morphology of these crystals has been systematically studied and compared with that of pure TGS crystal respectively. The lattice parameters of these crystals are determined. The pyroelectric and ferroelectric properties, such as pyroelectric coefficient, dielectric constant, dielectric loss, Curie point, spontaneous polarization, merit of figure, internal bias and hysteresis loop, have been comprehensively studied. The experiment results show that the dopants have entered the lattice of TGS crystal. The morphology and pyroelectric and ferroelectric properties of these crystals have changed regularly with dopant sorts and concentrations. The mechanism of the influence of dopants on the growth and properties of these crystals has been discussed. From the experiments, we validate that the function group in the dopant and the character of the dopant molecule itself–the polarity, the structure and the reciprocity, are two reasons which influence the morphology and the properties of TGS crystals.The properties of some doped TGS crystals have been improved in the experimental test: the dielectric constant of doped Trichloro acidacid TGS crystal is only 0.22 times of pure TGS crysal, and its quality fator is raised too; the pyroelectric coeffice and the quality factor of doped with Trifluoro acetic acid and Glycerin TGS crystal are two times and three times of the pure TGS crystal, and the Curie...