采用化学气相沉积(CVD)方法,在无催化剂的条件下,生长出了锑掺杂的超长、大尺寸ZnO微米线。测试表明微米线的平均长度可达1~2.5 cm,微米线中锑元素的含量约为3.1%(n/n)。此外,将挑选出的单根锑掺杂ZnO微米线以银浆为电极制作成热电发电...采用化学气相沉积(CVD)方法,在无催化剂的条件下,生长出了锑掺杂的超长、大尺寸ZnO微米线。测试表明微米线的平均长度可达1~2.5 cm,微米线中锑元素的含量约为3.1%(n/n)。此外,将挑选出的单根锑掺杂ZnO微米线以银浆为电极制作成热电发电机,并研究了微米线长度和微米线直径对器件输出性能的影响。研究表明当器件两电极之间的温差为20 K且两电极间微米线的长度为1.6 cm时,器件能够输出的最大电压和最大输出功率分别约为36 m V和10.8 n W,微米线的赛贝克系数约为-1.80 m V·K-1。此外,热电器件的输出电压随着微米线长度的增加而增大,随微米线直径的增加而减小。展开更多
Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode cont...Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode contacts in FET devices heavily influences the device performance, which makes it difficult to obtain the intrinsic electric properties of nanomaterials. Dielectric force microscopy （DFM）, a contactless method developed recently, can detect the low-frequency dielectric responses of nanomaterials without electric contact, which avoids the influence of electric contact and can be used to study the intrinsic conductivity of nanomaterials. Here we study the influences of surface adsorbates on the conductivity of ZnO nanowires （NWs） by using FET and DFM methods. The conductivity of ZnO NW is much larger in N2 atmosphere than that in ambient environment as measured by FET device, which is further proven by DFM measurement that the ZnO NW exhibits larger dielectric response in N2 environment, and the influence of electrode contacts on measurement can be ruled out. Based on these results, it can be concluded that the adsorbates on ZnO NW surface highly influence the conductivity of ZnO NW rather than the electrode contact. This work also verifies the capability of DFM in measuring electric properties of nanomaterials.展开更多
In this work, the Au/ZnO hybrid microstructure was fabricated by assembling Au nanoparticles(NPs) onto the surface of ZnO microrods, and an obviously improved ultraviolet(UV) emission of ZnO is observed in the hybrid ...In this work, the Au/ZnO hybrid microstructure was fabricated by assembling Au nanoparticles(NPs) onto the surface of ZnO microrods, and an obviously improved ultraviolet(UV) emission of ZnO is observed in the hybrid microstructure. About 27-fold enhancement ratio of the UV emission to the green band emission of ZnO is achieved. The underlying enhanced mechanism of the UV emission intensities can be ascribed to the charge transfer and the efficient coupling between ZnO excitons and Au surface plasmon(SP).展开更多
文摘采用化学气相沉积(CVD)方法,在无催化剂的条件下,生长出了锑掺杂的超长、大尺寸ZnO微米线。测试表明微米线的平均长度可达1~2.5 cm,微米线中锑元素的含量约为3.1%(n/n)。此外,将挑选出的单根锑掺杂ZnO微米线以银浆为电极制作成热电发电机,并研究了微米线长度和微米线直径对器件输出性能的影响。研究表明当器件两电极之间的温差为20 K且两电极间微米线的长度为1.6 cm时,器件能够输出的最大电压和最大输出功率分别约为36 m V和10.8 n W,微米线的赛贝克系数约为-1.80 m V·K-1。此外,热电器件的输出电压随着微米线长度的增加而增大,随微米线直径的增加而减小。
文摘Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode contacts in FET devices heavily influences the device performance, which makes it difficult to obtain the intrinsic electric properties of nanomaterials. Dielectric force microscopy （DFM）, a contactless method developed recently, can detect the low-frequency dielectric responses of nanomaterials without electric contact, which avoids the influence of electric contact and can be used to study the intrinsic conductivity of nanomaterials. Here we study the influences of surface adsorbates on the conductivity of ZnO nanowires （NWs） by using FET and DFM methods. The conductivity of ZnO NW is much larger in N2 atmosphere than that in ambient environment as measured by FET device, which is further proven by DFM measurement that the ZnO NW exhibits larger dielectric response in N2 environment, and the influence of electrode contacts on measurement can be ruled out. Based on these results, it can be concluded that the adsorbates on ZnO NW surface highly influence the conductivity of ZnO NW rather than the electrode contact. This work also verifies the capability of DFM in measuring electric properties of nanomaterials.
基金supported by the National Natural Science Foundation of China(No.U1404824)the Science&Technology Agency of Henan Province(No.142107000023)the Young Scientists Fund of Henan University of Science and Technology(No.09001635)
文摘In this work, the Au/ZnO hybrid microstructure was fabricated by assembling Au nanoparticles(NPs) onto the surface of ZnO microrods, and an obviously improved ultraviolet(UV) emission of ZnO is observed in the hybrid microstructure. About 27-fold enhancement ratio of the UV emission to the green band emission of ZnO is achieved. The underlying enhanced mechanism of the UV emission intensities can be ascribed to the charge transfer and the efficient coupling between ZnO excitons and Au surface plasmon(SP).
