[en] The sound generated from a periodically illuminated solid as a photoacoustic effects first discovered in 1881 is used to investigate the properties of materials. The PA spectra of ZnTe and ZnSe crystal were obtained by PAS method. The absorption spectrum of materials which is not accesible with optical spectroscopy can be obtained by PA spectroscopy. The PA signals were proportional to absorption coefficient and the energy bandgaps of ZnTe and ZnSe crystal were measured as 2.01 eV and 2.55 eV respectively. The characteristics of energy transition of ZnTe and ZnSe crystals were investigated as the direct allowed transition by PA spectroscopy. (Author)

[en] Photoluminescence of berillium-doped zinc telluride by diffusion has been studied. A band has been discovered with the energy in the radiation peak near the energy 2.373 eV, which is more than the basic state of free excitons in non-doped crystals but less than the widths of the forbidden zone. Layer by layer etching of specimens leads to disappearance of this band and to appearance of a new one in the region of energies of 2.2 eV

[en] Two 2D techniques for visualising the field of pulsed THz radiation (‘shadow’ and ‘interferometric’), which are based on the linear electro-optical effect with application of a ZnTe detector crystal 1 × 1 cm in size, are compared. The noise level and dynamic range for the aforementioned techniques are analysed and their applicability limits are discussed. (thz radiation)

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No abstract available

[en] Cadmium Zinc Telluride (CZT) is a proven material for high resolution radiation detector, which could be operative at room temperature. CZT could be used in applications including nuclear safety, composition analysis of spent nuclear fuel, astronomy, nuclear medicine, national security, and non destructive analysis. Tremendous efforts have been made in the development of CZT detector. Wider applications of CZT detector were mainly hindered by the difficulty to obtain the high quality CZT crystal. Material of high resistivity, low structural and microscopic defect concentrations should be supplied to make the application of CZT detector wider. Especially, the CZT crystal with high resistivity is required to measure the radiation with high energy resolution, and this requirement is only strongly required for radiation detector application. Bridgman growing method is generally used to grow the CZT crystal. We have developed the growing method of CZT material. In this paper, we will discuss the development of CZT crystal growing, and the recent result of our work

No abstract available

[en] The structure of ZnTe was studied using single-crystal high-temperature X-ray diffraction. The experimental data are analyzed within two models. In the first model, the structure is refined assuming anharmonic thermal atomic vibrations. In the second model, the static displacements of metal atoms (static disorder) are considered. The expressions for structure factors are derived for both models. The temperature dependence of the refined parameters is discussed. It is shown that although these models cannot be distinguished on the statistical basis, the model of anharmonic vibrations is the only physically reasonable one. 23 refs., 3 figs

[en] Efficient terahertz (THz) wave generation in strongly correlated organic compounds α-(ET)₂I₃ and α′-(ET)₂IBr₂ (ET:bis(ethylenedithio)-tetrathiafulvalene) was demonstrated. The spontaneous polarization induced by charge ordering or electronic ferroelectricity was revealed to trigger the THz-wave generation via optical rectification; the estimated 2nd-order nonlinear optical susceptibility for α-(ET)₂I₃ is over 70 times larger than that for prototypical THz-source ZnTe. Ultrafast (<1 ps) and sensitive (∼40%) photoresponse of the THz wave was observed for α-(ET)₂I₃, which is attributable to photoinduced quenching of the polarization accompanied by insulator(ferroelectric)-to-metal transition. Modulation of the THz wave was observed for α′-(ET)₂IBr₂ upon the poling procedure, indicating the alignment of polar domains

[en] The dispersion effect on the probe pulse and its consequence of distorting the measured THz pulse propagating through a nonlinear crystal, ZnTe in this study, are investigated. By fusing the Yee algorithm and the FDTD method, temporal and spectral evolution of an emerging THz pulse as measured by using probe pulses with different time durations are calculated. A simple formula is proposed to calculate the optimum width of the probe pulse versus the thickness of the crystal to minimize the error on measuring the THz pulse