Cathodoluminescent and electrical properties of an individual ZnO nanowire with oxygen vacancies

A single ZnO nanowire with intrinsic oxygen vacancies is utilized to fabricate four-contact device with focus ion beam lithography technique. Cathodoluminescent spectra indicate strong near-UV and green emission at both room temperature and low temperatures. Experimental measurement shows the temperature-dependent conductivity of the ZnO nanowire at low temperatures （below 100 K）. The further theoretical analysis confirms that weak localization plays an important role in the electrical transport, which is attributed to the surface states induced by plenty of oxygen vacancies in ZnO nanowire.     

Visualizing interface states in In2Se3–WSe2 monolayer lateral heterostructures

Recent findings of two-dimensional(2D) ferroelectric(FE) materials provide more possibilities for the development of 2D FE heterostructure electronic devices based on van der Waals materials and the application of FE devices under the limit of atomic layer thickness. In this paper, we report the in-situ fabrication and probing of electronic structures of In₂Se₃–WSe₂ lateral heterostructures, compared with most vertical FE heterostructures at present. Through mole...     

Measuring thermoelectric property of nano-heterostructure

A method of measuring the thermoelectric power of nano-heterostructures based on four-probe scanning tunneling microscopy is presented. The process is composed of the it in-situ fabrication of a tungsten-indium tip, the precise control of the tip-sample contact and the identification of thermoelectric potential. When the temperature of the substrate is elevated, while that of the tip is kept at room temperature, a thermoelectric potential occurs and can be detected by a current-voltage measurement. As an example of its application, the method is demonstrated to be effective to measure the thermoelectric power in several systems. A Seebeck coefficient of tens of μV/K is obtained in graphene epitaxially grown on Ru (0001) substrate and the thermoelectric potential polarity of this system is found to be the reverse of that of bare Ru (0001) substrate.     

Thermoelectric-transport in metal/graphene/metal hetero-structure

We investigate the thermoelectric-transport properties of metal/graphene/metal hetero-structure. We use a single band tight-binding model to present the two-dimensional electronic band structure of graphene. Using the Landauer--Butticker formula and taking the coupling between graphene and the two electrodes into account, we can calculate the thermoelectric potential and current versus temperature. It is found that in spite of metal electrodes, the carrier type of graphene determines the electron motion direction driven by the difference in temperature between the two electrodes, while for n type graphene, the electrons move along the thermal gradient, and for p type graphene, the electrons move against the thermal gradient.