Vertically Aligned Few-Layered Graphene-Based Non-Cryogenic Bolometer

Anil K Yadav,Kiran Shankar Hazra,Renu Rani,Devi Shanker Misra,Navneet Soin,Anirban Kundu,Saba Mehsar Khan,James Mclaughlin

doi:10.3390/c5020023

Abstract

In this study, we report the photoresponse of vertically aligned few-layered graphene (VAG) upon infra-red (IR) irradiation at room temperature. Four probe measurements showed the current–voltage (I–V) characteristic of electrical switching during pulsed IR irradiation. The photoresponse reported here for VAG was significantly higher than that reported for carbon nanotube (CNT) samples. Our investigation shows that such a photoresponse arose solely from the bolometric effect, where the conductivity changed with temperature. The resistance magnitude of the VAGs increased ~two fold for each 6 °C increase in temperature. Also, the Thermal Coefficient of Resistance (TCR) in this region was ~11%/K, which is the highest TCR value reported for any carbon nanomaterial.

Highlights

Among the carbon materials, carbon nanotubes (CNTs) have already proven to be a very useful material for infrared (IR) photoresponse
We have thoroughly investigated the IR photoresponse of vertically aligned graphene (VAG) at a normal room temperature and have reported an enhanced IR photoresponse in comparison with reports on the photoresponse of CNT
It is evident that the samples were vertically aligned and the graphene platelets had a curved structure and intercalated randomly to Figure 2a shows the Scanning electron microscopy (SEM) images of the grown vertically aligned few-layered graphene (VAG) samples

Summary

Introduction

Carbon nanotubes (CNTs) have already proven to be a very useful material for infrared (IR) photoresponse. Several reports have confirmed that both the single-walled carbon nanotubes (SWNT) and the multi-walled carbon nanotubes (MWNT) have an obvious response to IR irradiation. Itkis et al have shown the sensing of IR by a suspended CNT network at a cryogenic temperature in a vacuum [1]. An IR photoresponse has been reported for individual isolated CNT or CNT–polymer composites, even at room temperature and with normal pressure [2,3,4]. There has been debate over whether the origin of the photoresponse in CNTs is due to (1) photo-induced excitons, (2) interband transition or (3) the bolometric effect. Freitag et al [5]

Methods

Discussion

Conclusion