| Micro/nanowires are widely used in microelectronic devices,energy conversion,aerospace and many other fields due to their excellent merits.It is becoming more and more important to study their thermophysical properties.In this paper,micro/nanowires are used as the main research object,and the preparation of nanowires and the methods for measuring the thermophysical properties are studied.First of all,silicon nanowires are prepared by metal-assisted chemical etching method.By controlling the times of reactive ion etching and chemical etching,silicon nanowires with uniform thickness,controllable size and good quality are obtained.The nanowires are transferred using the probe platform system.And then,we improve the laser flash-Raman spectroscopy method for the different laser flash spectroscopy method.The method can directly measure the thermal diffusivity of micro/nanowires with unknown laser absorption coefficient.The accuracy of the method is verified by measuring a single platinum wire with a length of 3.30 mm.Furthermore,a single silicon nanowire with a length of 27.6μm is measured by the method.The experimental results show that the thermal diffusivity of the silicon nanowire is significantly lower than bulk material,and the value decreases with increasing of temperature.At last,T-type Raman spectroscopy method is developed for micro/nanowires that are not suitable for Raman spectroscopy method.The thermal resistance and thermal conductivity of the wire to be tested are obtained by comparing the changes of temperature rise before and after lapping the wire to be tested.Using the platinum wire as the sensor,the thermal conductivity of a single platinum wire with a length of 2.33 mm is measured,and the accuracy of the method is verified.A single graphitized carbon fiber with a length of 3.87 mm is also measured,and the thermal conductivity increases first and then decreases with increasing of temperature. |
PDF Full Text Request