| Wide bandgap semiconductors have wide bandgap (≥2.3eV), small dielectric constant,strong ability of radiation and high electron mobility, which have been the third generationsemiconductor. Wide bandgap semiconductors have the applications on the violet, blue,green and white light emitting diode; and the high frequency, high power, high temperatureresistant and anti radiation devices. Doping ions into the wide bandgap semiconductorscould modify some properties of materials, such as, the optical properties, electricalproperties, magnetic properties and even the morphology of the materials. In this paper,some kinds of the doping wide bandgap one-dimensional semiconductors were synthetizedby using the chemical vapor depositon (CVD) method. The optical properties and thepotential applications of these materials were also investigated. The details are followed asbelow:1. Zn doped CdS nanobelts are synthetized by the CVD method assisted with H2gas.Through the results of XRD, it is confirmed that zinc ions diffuse into the lattice of CdSnanobelts rather than alloy together. The PL spectrum of Zn doped CdS nanobelts showstwo distinct bands at~510nm and~600nm, which are obtained the yellow-colored light bymixed the green and red colors. The detailed chromaticity and brightness of the light can beengineered by the dopant concentration and the pumping power, which are used to controlthe dominant wavelength to any fine yellow color, and even cover the sodium-yellow-lineof589nm. Therefore, Zn doped CdS nanobelts have the potential applications for thesource of yellow-color light. Moreover, under the excitation of femtosecond laser with thewavelength of800nm, the two-photon excitation of Zn doped CdS nanobelts foryellow-light generation is also studied, and the threshold of the two-photon exciation of Zndoped CdS nanobelts is lower than that of pure CdS nanobelt.2. Basing on the optical properties of pumping-power-dependent emission, single-chipZn doped CdS nanobelts are developed to monitor injected laser power and detect theprofile of laser focal spots visually in the micron region through the emitting color changes.The intensity ratio of these two emitting band is monotonously changing by the variety ofthe pumping power, so the laser power and focus spot distribution can be monitoredquantitatively by the on-chip nanobelts. Morever, for confirming that the single-chip Zndoped CdS nanobelts are stable and effective, more than two thousand cycles of pumping laser power increasing and decreasing periodically are applied on the Zn doped CdSnanobelts chip, accompanied by emission-color switching between orange-yellow emissionand green emission. Therefore, the single-chip Zn doped CdS nanobelts have potentialapplication as a laser power monitoring tool for opticaaly integrated microcircuits.3. The ZnS nanobelts with periodically modulated thickness were synthesized througha controllable one-step CVD method. These ZnS nanoblets show a pattern of periodical“color-bars” under white light illumination, resulting from the periodic thickness changesalong the ZnS nanobelt with the measuring of XRD, SEM, s-SNOM, EDS and Ramanspectra. The possible growth mechanism of these ZnS nanobelts can be described asfollowed that the segment of ZnS:Mn parts might be formed at first; and then Mn ions aregathered in ZnS nanobelts with the prolonged heating time and the continuous carrier gas,which might lead to the phase separations occur and the two segments of ZnS andZnS+MnS might be periodically formed; at last, the ZnS nanobelts with periodicallymodulated thickness are formed with the changing of the growth rate. Moreover, the roomtemperature resonance PL spectrum of these ZnS nanobelts exhibits a dominant UVemission and a weak broad green emission band. |
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