Intense wide-band photoluminescence (PL) was observed at room temperature from both SiC thin films grown on silicon substrates by hot-filament chemical vapor deposition and anodized SiC thin films formed by electrochemical anodization in HF-ethanol solution. It was found that prolonged irradiation with ultraviolet light from a He-Cd laser (325nm, 10mW) generally enhanced the PL intensity of as-grown SiC but induced a new PL band in anodized SiC at room temperature. The light-induced PL emission in anodized SiC was centered at the energy between 2.1 and 2.2eV in comparison with the initial peak position of about 1.9eV. These effects were also temperature dependent.

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.

Optoelectronic characteristies of the SiCl-ZGeZ/SiC heterojunction photodiode are simulated using MEDICI after the theoretical investigation of key properties for SiCl-xGex. The calculations show that SiCl-xGex/SiC with x=0.3 may have a small lattice mismatch with 3C-SiC and a good response to the visible light and the near infrared light. The response spectrum of the SiCl-xGex/SiC heterojunction photodiode, which consists of a p-type SiCl-xGex absorption layer with a doping concentration of 1×1015cm-3 ,a thickness of 1.6μm and x=0.3, has a peak of 250mA/W at 0.52μm and the peak can even reach 102mA/W at 0.7μm.

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

Resonant tunneling in multiple-barrier structures with arbitrary potential profile is studied theoretically. Analytical expressions of the transmission coefficient and the resonance condition are derived by taking into account the mass difference between well and barrier layers. The basic barrier unit in the periodic multiple-barrier structure may be a compound-barrier structure, and the simplest compound-barrier unit is the double-barrier unit. Two independent resonance conditions exist in the multiple-barrier structures with compound-barrier unit and both the subband gap energy and the energy value at the center of the subband gap may be determined analytically and independently for the multiple-barrier structure with doublebarrier unit.