Lan Li Chen

Effect of Hydrothermal Synthesis Time and Solvent Replacement on ZrO2 Sols

ZrO2 sols were obtained by hydrothermal synthesis. With different hydrothermal synthesis time, ZrO2 particle size varied from 5nm to 16nm. And ZrO2 thin films were prepared with spin coating method. ZrO2 thin films were characterized or examined by many kinds of instruments. And 1-on-1 laser-induced damage threshold tests on ZrO2 films were carried out. Refractive index and thickness of the ZrO2-PVP films were measured by means of automatic scanning spectroscopic ellipsometer and the refractive index of ZrO2 -PVP film changed with the addition of PVP content.

Designing of Thermistor Digital Thermometer Based on Unbalanced Electric Bridge

The temperature measure principle of unbalanced electric bridge is expounded by means of temperature characteristics of thermistor. A method to deal with nonlinear function is proposed. The experiment indicts that the thermistor digital thermometer based on unbalanced electric bridge is in accordance with the design request. Its circuit is simple and it has certain practical value.

Influence of Hydrogen Dilution on Microstructure of μc-Si: H Films

The influence of hydrogen dilution (D) on glass/stainless steel-based intrinsic amorphous/microcrystalline silicon thin film prepared was investigated by PECVD technology. The crystallization ratio and grain size of the silicon thin film at different hydrogen dilution is studied. The results reveal that the crystallization ratio and grain size of silicon thin film changed along with D. The crystallization ratio and grain size of the silicon thin film become larger when D is higher. However, the deposition rate is slow when the D value is too high. On this work, optimal μc-Si:H can be obtained at D of about 98% in the suitable experimental conditions.

THE FABRICATION AND PHOTOLUMINESCENCE PROPERTY OF ZNO NANOSHEETS

Sheet-shaped zinc oxide nano-particles were prepared by hydrothermal method. The zinc oxide nanosheets were characterized by X-ray diffraction (XRD)，scanning electron microscopy(SEM) and photoluminescence spectrum (PL) at room temperature. The strongest diffraction apex of the nanosheet-shaped zinc oxide is assigned to crystal planes and exhibits obvious preferred orientation which is different from that of the general zinc oxide. The results show that ZnO nanosheets with about 1000nm×600nm×60 nm are obtained. The growth mechanism of the ZnO nanosheets was discussed.

Microstructural and Luminescent Properties of ZnO Prepared by Chemical Solution Growth Method

In this thesis, ZnO nanostructures with different morphologies were synthesized on silicon substrates by chemical solution growth method from Zinc acetate and methenamine aqueous solution at 70°C for 4 hours. Its morphologies by SEM and its crystal structures by XRD were studied．Its photoluminescence spectrum was also measured．And possible mechanisms of the growth and the photoluminescence of ZnO were proposed to explain the experimental result．

Microstructure and Photoluminescence Study of ZnO Films Prepared by Thermal Oxidation of Zn Metallic Films in Air

In this thesis, Zn films were deposited on silicon substrates by high-speed galvanization, and then were treated in Muffle Resistance Furnace at 700°Cin an open-air environment. Polycrystalline ZnO films covered with ZnO nanorods were grown. Its morphologies were studied by SEM and its crystal structures were studied by XRD．Its photoluminescence spectrum was also measured．And possible mechanisms of the growth and the photoluminescence of ZnO nanorods were proposed to explain the experimental result．

The Preparation of p-PS and its Photoluminescence Properties

In this research, p-type porous silicon was successfully fabricated with a typical electrochemical etching method. The mixed solution of HF and absolute ethyl alcohol with different volume ratio was used as the electrolyte in this experiment. The anodic current density was 20 mA/cm2～60 mA/cm2. The luminous intensity of the PS samples increased with the increasing of the current density, the peaks of PL first red shift (from 692.1nm to 727.9nm) then blue shift (from 727.9nm to719.6nm). With the increasing of the concentration of HF, PS luminous intensity gradually decreases, and the peaks of PL gradually occurs red shift. And possible mechanisms of the growth and the photoluminescence of porous silicon were proposed to explain the experimental result．

Improvement in the Transport of Charge Carriers in Tunnel Junctions of Silicon-Based Thin Film Tandem Solar Cells

We report new results on a tunneling junction for tandem solar cells using a nano-structured amorphous silicon p+ layer (na-Si p+) as the recombination layer inserted between the n layer and the p layer. Devices were characterized by their dark current-voltage behavior (I-V), activation energy (Ea) and quantum efficiency (QE). The result shows that the tunnel junction with a na-Si p+ insertion layer has higher recombination rates with higher density of defect states of about 2.7×1019cm-3 , lower resistance with activation energy of 22meV. The tunnel junction with a na-Si p+ insertion layer could be easily integrated into the tandem solar cell deposition process.

Investigation on High Laser-Induced Damage Threshold of ZrO2-PVP Thin Films by Hydrothermal Synthesis

ZrO2 –PVP thin films were prepared with sol-gel and spin coating method. The films were characterized or examined by many kinds of instruments. With different heating treatment temperature, the surface toughness Ra of ZrO2-PVP thin films are different from 0.421nm to 0.738. And 1-on-1 laser-induced damage threshold tests on ZrO2 films were carried out with a Q–switched Nd-YAG high power laser at 1064 nm with a pulse width of 1ns. The experimental results showed that ZrO2 thin films could achieve good surface micro morphology and high laser induced damage threshold.

Sol-Gel Derived ZrO2-PVP Coatings with High Laser-Induced Damage Threshold

ZrO2 and ZrO2-PVP sol was obtained by hydrothermal synthesis. And the thin films were prepared with spin coating method. ZrO2 thin films were characterized or examined by many kinds of instruments. Fourier-transform infrared spectroscopy was employed and some infrared absorption peaks weakened when the heating temperature increased. And 1-on-1 laser-induced damage threshold tests on ZrO2 films were carried out. Refractive index and thickness of the ZrO2-PVP films were measured by means of automatic scanning spectroscopic ellipsometer and the refractive index of ZrO2 -PVP film changed with the addition of PVP content.