Papers by Author: Jung Chuan Fan

Abstract: Sr-doped LaTiO₃ (SLTO) thin epitaxial films on LaAlO₃ (100) have been fabricated by the off-axis rf magnetron co-sputtering system. The dopant Sr²⁺ ions were expected substituting La³⁺ ions in the films to introduce the hole carriers. The X-ray diffraction shows that the [001] direction of the SLTO films is perpendicular to the substrate surface. The in-situ grown specimens were measured the temperature dependence of resistivity and the Hall coefficients to study the transport properties. The Hall measurements show that the carrier is electron for Sr-doping over 16%. The temperature dependence of the resistance shows that the n-type films are metallic and deviate from free electron gas model obviously. We found the behaviour could be well described by the small-polaron coherent motion model.

Abstract: The semiconducting property of carbon nanotubes have been investigated by the luminescence measurement. The morphology of carbon nanotubes has been detected by the scanning electric microscope, and the X ray diffraction determines the atomic structure of carbon nanotubes. The carbon nanotubes can be luminescence under laser irradiation. Using the photoluminescence measurement, the emitting spectrum of carbon naotubes is very spread in a near-red emission range and a main peak at 1.3 eV . The temperature dependent of photoluminescence effect indicates that the semiconducting property of carbon nanotubes is very clearly. According to the thermally photoluminescence experiment, the luminescent property of carbon nanotubes is due to the center of energy trap of defect. It is suggested that the luminescence of the semiconducting property result is dominated by the electron trap of defect in the carbon nanotubes system.