大面积α-Fe2O3纳米线及纳米带阵列的制备研究

以铁箔为原材料和基片,通过控制热氧化过程中的宏观实验条件(载气流量及其组分、压强、温度分布和反应时间等),实现了α-Fe₂O₃一维纳米结构的可控生长,获得了大面积(10mm×10mm)、单分散性好、沿［110］方向生长的α-Fe₂O₃纳米带或纳米线阵列. 对不同宏观实验条件下所制备的样品进行形貌和晶格结构表征和分析,认为热氧化过程中α-Fe₂O₃一维纳米结构的生长遵循类似气- 关键词： 2O₃')" href="#">α-Fe₂O₃ 一维纳米结构 热氧化法     

大面积α-Fe2O3纳米线及纳米带阵列的制备研究

以铁箔为原材料和基片,通过控制热氧化过程中的宏观实验条件(载气流量及其组分、压强、温度分布和反应时间等),实现了α-Fe2O3一维纳米结构的可控生长,获得了大面积(10mm×10mm)、单分散性好、沿[110]方向生长的α-Fe2O3纳米带或纳米线阵列. 对不同宏观实验条件下所制备的样品进行形貌和晶格结构表征和分析,认为热氧化过程中α-Fe2O3一维纳米结构的生长遵循类似气-固机制的顶端生长模式,生长点铁原子和氧原子比是控制α-Fe2O3一维纳米结构生长的关键因素.     

Controlling the electronic structure of SnO2 nanowires by Mo-doping

Mo-doped SnO2 (MTO) nanowires are synthesized by an in-situ doping chemical vapour deposition method. Raman scattering spectra indicate that the lattice symmetry of MTO nanowires lowers with the increase of Mo doping, which implies that Mo ions do enter into the lattice of SnO2 nanowire. Ultraviolet-visible diffuse reflectance spectra show that the band gap of MTO nanowires decreases with the increase of Mo concentration. The photoluminescence emission of SnO2 nanowires around 580 nm at room temperature can also be controlled accurately by Mo-doping, and it is extremely sensitive to Mo ions and will disappear when the atomic ratio reaches 0.46%.     

Hydrothermal synthesis and chromic properties of hexagonal WO3 nanowires

This paper reports that highly purified hexagonal WO 3 nanowires are synthesized by a simple hydrothermal method.The as-synthesized WO 3 nanowires are investigated in detail by ultraviolet-visible-near infrared spectroscopy and electrical transport measurements under different conditions.It finds that the optical band gap and the diffuse reflection coefficient in the wavelength region above 450 nm of WO 3 nanowires decrease observably upon exposure to ultraviolet light or NH 3 gas.It is also found that there are electrons being trapped or released in individual WO 3 nanowires when scanning bias voltage in different directions upon exposure to ultraviolet and NH 3 gas.The experimental results suggest that the chromic properties might be attributed to the injection/extraction of hydrogen ions induced by ultraviolet light irradiation in air or creation/annihilation of oxygen vacancies induced by NH 3 gas exposure,which serve as colour centres and trap electrons as polarons.The experimental results also suggest that the hexagonal WO 3 nanowires will be a good candidate for sensing reduced gas such as NH 3.     

化学气相沉积法制备Sn2S3一维纳米结构阵列

运用化学气相沉积法(CVD), 直接以Sn和S为原料分区加热蒸发, 通过控制温度分布、气压、载气流量和金属铅纳米颗粒分布等宏观实验条件, 成功制备大面积Sn₂S₃一维纳米结构阵列. 扫描电子显微镜(SEM)图片显示: Sn₂S₃一维纳米结构的横向尺度在100 nm左右, 长约几个微米. X射线衍射（XRD）谱显示: 所制备样品的晶体结构属于正交晶系, 沿[002]方向生长. 紫外-可见漫反射谱表明Sn₂S₃一维纳米结构是带隙为2.0 eV的直接带隙半导体. 讨论了温度分布和金属铅纳米颗粒对Sn₂S₃一维纳米结构生长的影响, 并指出其生长可能遵循气-固(V-S)生长机理.