Experimental Study On Electrical,Thermal And Magneto Transport Properties Of Gold Nanofilms

Gold nanofilms are widely used as self-heating thermometer in the field of micro/nanoscale measurement.The electrical and thermal transport properties in the presence and absence of strong magnetic fields are of great importance for fundamental research and engineering systems.In this thesis,the electrical,thermal and magnetoresistance transport properties of gold nanofilms have been experimentally studied,and the rectification characteristics caused by the Schottky contact between gold nanofilm as self-heating thermometer and two-dimensional material Re Se₂ have also been studied,and the underlying mechanisms have been explored.The electrical resistivity and temperature coefficient of resistance of suspended gold nanofilms with different length have been simultaneously studied by using the direct current heating method.The applicability of direct current heating method at low temperatures has been tested and optimized.Through the study of the temperature dependence of the electrical transport properties of the films,it is found that only considering surface and grain boundary scattering cannot predict the resistivity and temperature coefficient of resistance at the same time.By introducing the enhanced surface electron-phonon interactions,the electrical transport properties of the films can be well described in the whole temperature range.The resistivity and thermal conductivity of the gold nanofilm in the temperature range of 2-300 K and the magnetic field strength range of 0-14 T have been studied by the optimized direct current heating method.It has been found that the maximum relative change rates of the influence of strong magnetic field on the resistivity and thermal conductivity of the film are only 1.2%and 2.2%respectively,which indicates that the film can be used as a self-heating thermometer in the measurements under magnetic field.The magnetoresistance of the film takes a maximum value at 10 K for different magnetic field strength and obeys Kohler's rule.The current-voltage characteristics of two-dimensional material Re Se₂ in a temperature range of 273-340 K have been studied by using the suspended gold nanofilm as a self-heating thermometer.The rectification behavior of Schottky contact between the film and Re Se₂ is observed experimentally,and the saturation current and ideality factor of the Schottky contact are studied by the thermionic emission theory.