Ultra-sensitive graphene sensor for measuring high vacuum pressure

Sung Il Ahn,So Young Choi,Jung-Chul Park,Ju Ra Jung,Min Hwa Son,Yu Jin Hong

doi:10.1038/s41598-017-13038-3

Abstract

We demonstrate here that several different graphene nanoribbon (GNR) samples can be separated from the GNR mixture synthesized by conventional methods. The sheet resistance of the purified GNR gradually decreased with decreasing pressure at 30 °C, whereas it increased at 100 °C. A hypothesis based on van der Waals attractive interactions between GNR sheets was introduced to explain this finding. This hypothesis verified by the shifted main peaks in vacuum X-ray diffraction spectra: 0.022 nm and 0.041 nm shifts were observed for reduced graphene oxide (RGO) and GNR, respectively. Theoretical calculations indicated that, for RGO, the shifted distance was similar to the calculated distance. The response of the GNR sensor to pressure changes occurred rapidly (in seconds). The normalized response time of each sample indicated that sensor using GNR reduced the tailing of the response time by shortening the diffusion path of gas molecules. The sensitivity of the GNR sensor was three times that of RGO in the given pressure range. Moreover, the sensitivity of GNR was much larger than those of the most popularly studied pressure sensors using Piezoresistivity, and the sensor could detect vacuum pressures of 8 × 10–7 Torr.

Highlights

Many pressure sensors using graphene and its derivatives have been studied such as field emission pressure sensors,[1] a graphene squeeze-film pressure sensor,[2] and micro-electro-mechanical systems piezoresistive pressure sensors[3,4,5,6,7,8] which determine the strain produced in graphene by an external pressure
We have previously investigated the use of Van der Waals (VDW) attractive force between reduced graphene oxide (RGO) sheets for application in a vacuum pressure sensor.[9]
Based on the VDW force and thermal vibration modes of a graphene sheet,[12,13] we propose two different physical motions of carbon clusters on adjacent RGO sheets with voids in a film and thereby electrical responses against vacuum pressure (See Fig. 1a and b)

Summary

Introduction

Many pressure sensors using graphene and its derivatives have been studied such as field emission pressure sensors,[1] a graphene squeeze-film pressure sensor,[2] and micro-electro-mechanical systems piezoresistive pressure sensors[3,4,5,6,7,8] which determine the strain produced in graphene by an external pressure. Based on the VDW force and thermal vibration modes of a graphene sheet,[12,13] we propose two different physical motions of carbon clusters on adjacent RGO sheets with voids in a film and thereby electrical responses against vacuum pressure (See Fig. 1a and b).

Results

Conclusion