Highly sensitive NO2 sensors by pulsed laser deposition on graphene

Abstract

Graphene as a single-atomic-layer material is fully exposed to environmental factors and has therefore a great potential for the creation of sensitive gas sensors. However, in order to realize this potential for different polluting gases, graphene has to be functionalized -adsorption centers of different types and with high affinity to target gases have to be created at its surface. In the present work, the modification of graphene by small amounts of laser-ablated materials is introduced for this purpose as a versatile and precise tool. The approach has been demonstrated with two very different materials chosen for pulsed laser deposition (PLD) -a metal (Ag) and a dielectric oxide (ZrO2). It was shown that the gas response and its recovery rate can be significantly enhanced by choosing the PLD target material and deposition conditions. The response to NO2 gas in air was amplified up to 40 times in the case of PLD-modified graphene, in comparison with pristine graphene, and it reached 7-8% at 40 ppb of NO2 and 20-30% at 1 ppm of NO2. The PLD process was conducted in a background gas (5 x10 -2 mbar oxygen or nitrogen) and resulted in the atomic areal

Annealing effect on UV-illuminated recovery in gas response of graphene-based NO2 sensors

“…9 Several room temperature NO 2 gas sensors based on graphene have been reported in the past decade. [10][11][12] For example, ppb level sensing was demonstrated under high vacuum and argon environments. 11 In order to detect NO 2 in air environment, Kodu et al deposited ZrO 2 and Ag nanoparticles on the graphene surface by pulsed laser deposition and reported detection down to 40 ppb, 12 but the recovery to the original baseline was incomplete.…”

Highly Sensitive NH3 Sensors Using CVD and Epitaxial Graphene Functionalised with Vanadium(V) Oxide: A Comparative Study

“…In the course of functionalisation a high number of point defects is formed by bombardment with high-energy atoms of PLD plasma. The induced defects are further modified through the adding of functionalising oxide material [3,9].…”

Graphene functionalised by laser-ablated V2O5 for a highly sensitive NH3 sensor

“…First, under UV exposure, the sensor responses were at least 2 to 3 times faster. Second, without UV illumination, the recovery of the signal in pure air was almost absent in the case of ZrO 2 , and only partial recovery of the signal occurred in the case of Ag [ 14 ].…”

“…The possibility to evaporate practically any solid material, tune the kinetic energy of particles between 0.1 to 1000 eV, as well as the ability to control the amount of deposited material from about 1/100th of a monolayer per laser pulse are the advantages worth mentioning. The method of PLD has recently been applied to improve the nitrogen dioxide (NO 2 ) sensing properties of chemical vapour deposition (CVD) grown, single-layer graphene in our previous work, using ZrO 2 and Ag for functionalisation [ 14 ].…”