Temperature Difference Measurement between Nanogap Fabricated by Cleavage of Single Crystal Silicon Using Raman Microscopy

Abstract

　　　Nanogap is expected to be applied to thermionic generation. However, the nanogap fabricated by microfabrication technologies have small area and non-parallel rough surfaces. In this research, we fabricated nanogap by cleaving single crystal silicon beam on (111) plane with silicon-on-insulator microelectromechanical system (SOI-MEMS) device and obtained nanogaps with 40 nm － 1.47 μm distance gap and parallel smooth surfaces of 28 － 40 μm². Temperature difference between nanogap was measured using Raman microscope for evaluation of thermal transfer coefficient via nanogap. As a result, 45.0 - 61.9 K temperature difference was observed, and it was confirmed that the thermal transfer coefficient is significantly small. This indicates that the fabricated nanogaps were successfully formed and not in contact, and these methods are useful to evaluate the thermal properties of nanometer scale vacuum space.