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
Multiwalled-carbon nanotubes coated with nano-crystalline zinc oxide （ZnO） was prepared by in situ growth of nano zinc oxide on the surfaces of carbon nanotubes through hydrothermal method. X-ray diffraction, transm...Multiwalled-carbon nanotubes coated with nano-crystalline zinc oxide （ZnO） was prepared by in situ growth of nano zinc oxide on the surfaces of carbon nanotubes through hydrothermal method. X-ray diffraction, transmission electron microscopy and scanning electron microscopy analysis techniques were used to characterize the samples. It was observed that a layer of nano-crystalline ZnO with the wurtzite hexagonal crystal structure was uniformly coated on the nanotube surfaces with good adhesion, which resulted in the formation of a novel ZnO-nanotuhe nano composite. In this work, the carbon nanotubes decorated by metal oxide nanoparticles were synthesized by a simple chemical-solution route which is suitable for the large-scale production with low cost.展开更多
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.
文摘Multiwalled-carbon nanotubes coated with nano-crystalline zinc oxide （ZnO） was prepared by in situ growth of nano zinc oxide on the surfaces of carbon nanotubes through hydrothermal method. X-ray diffraction, transmission electron microscopy and scanning electron microscopy analysis techniques were used to characterize the samples. It was observed that a layer of nano-crystalline ZnO with the wurtzite hexagonal crystal structure was uniformly coated on the nanotube surfaces with good adhesion, which resulted in the formation of a novel ZnO-nanotuhe nano composite. In this work, the carbon nanotubes decorated by metal oxide nanoparticles were synthesized by a simple chemical-solution route which is suitable for the large-scale production with low cost.
