Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline Sic samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650

Cubic silicon carbide (3C-SiC) is the most promising material for active devices. Most researches of 3C-SiC epitaxial technology have been focused on chemical vapor deposition (CVD) in the past, but the growth rate of CVD is low. We attempt to grow epitaxial 3C-SiC on Si by sublimation method according to bulk sublimation growth technology. The typical sample is characterized by X-ray diffraction and Raman scattering spectroscopy. The results reveal that the sample is well crystalline.

If a Darlington transistor is triggered by the photocurrent output from an individual photodiode, the electromagnetic interference (EMI) problem may still exist because the direct input of the Darlington is an actually electronic signal. To eliminate the EMI problem completely, we propose an absolutely light-activated Darlington transistor made of SiC, in which p-SiCGe/n-SiC heterojunction is employed to produce a base current by means of optical illumination. Performance of the novel light-activated power switch was simulated using MEDICI tools, which has shown that the light-activated device has very good switching characteristics especially for a triggering light intensity greater than 0.23 W/cm2. For a relatively weak light, the device can be switched to the ON state only for a higher bias voltage.

Pb (Zr, Ti,) O, (PZT) films were prepared on the ITO coated glass plates in sol-eel dip-coating process and post-annealing at different temperatures. The structural properties of the films were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is shown that the PZT ferroelectric thin films with (110) preferential orientation and well-crystallized perovskite structure can be obtained after annealing at 680℃ for 30 minutes. The P-E hysteresis loops were measured by the Sawyer-Tower test system with a compensation resistor at room temperature. Values of the remanent polarization (P,) and the coercive electric field (E,) are 19.36C/em2 and 95kV/em, respectively, for the prepared PZT thin films. The relative dielectric constant c' and the dissipation factor tg• of the PZT thin films are equal to 639 and 0.23. respectively, which were measured in a LCR meter.

Crystalline SiC samples were prepared in solidification of silicon melt saturated by carbon solved from the inner wall of a graphite crucible. The crystalline structure of the samples was analysed in Raman spectroscopy and confirmed as 3C-SiC both in x-ray diffraction and x-ray photoelectron spectroscopy (XPS). The Raman spectra of the samples present a strong sharp peak located at 796.3cm-1 with a full width at half maximum about 6cm-1 and three weak peaks broadened around 1525.6, 1631.4 and 1719.1cm-1, respectively. The former belongs to the transverse optical phonons of 3C-SiC, while the latter can be attributed to the second-order scattering. However, the longitudinal optical mode of 3C SiC has not been found for our samples. An additional broadened peak at 532.2 cm-1 may imply the existence of some lattice defect in the samples, which is related to nitrogen introduced unintentionally into the lattice in the growth process and confirmed in XPS of N 1s binding energy centred at 400.9 eV.