The THM growth technology for 100 mm diameter CdTe single crystals has been intensively developed. In consequence of the optimization of growth conditions, we have succeeded in controlling growth interface shape and growing 100 mm diameter CdTe single crystals with 300 mm in length. Concerning the behavior of Te inclusions in the grown crystal, their size and density were investigated by IR transmission microscopy. The size distribution of Te inclusions was divided into two groups, and the density of them was less than 1 10 5 cm 3 . Charge transport properties of the grown crystal were investigated by using the " -model" spectral fitting method, and were found to be quite uniform all over the wafer. To investigate the homogeneity of radiation detector performances, Ohmic type and Schottky type detectors with 4 mm 4 mm 1 mm were fabricated from the left half and the right half of the 100 mm diameter wafer, respectively. Standard deviations of their energy resolutions for the 122 keV line from 57 Co were less than 6%. This excellent uniformity is essential for the room temperature semiconductor detectors in the major application areas, such as medical imaging, non-destructive inspection and homeland security.
The electrooptic characteristics of a twisted nematic (TN) liquid crystal display (LCD) fabricated by doping Ag nanoparticles protected with NLC, 5CB (K-15, Merck) molecules have been investigated, and it is shown that the device exhibits a unique electrooptic response characteristic that is sensitive to the high-frequency components of the operating voltage together with the conventional root-mean-square voltage response. We call this device frequency modulation (FM) TN-LCD. The FM-TN-LCD is switched by switching the frequency of the operating voltage while its amplitude is kept unchanged. As an example, the frequency switched from 20 Hz to 500 Hz or 50 Hz to 2 kHz, and the switching is performed with the time constant of 21 ms for the rising process and 3 ms for the falling process. This device shows a peculiar response to a burst AC square wave, where the decay time is reduced by several times compared to that of an undoped TN-LCD. The mechanism of the FM-TN-LCD is investigated through the study of its dielectric properties.
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