TY - JOUR

T1 - Mapping nanoscale dynamic properties of suspended and supported multi-layer graphene membranes via contact resonance and ultrasonic scanning probe microscopies

AU - Mucientes, Marta San Juan

AU - Lulla, Kunal

AU - Peasey, Adrian

AU - Shao, Shouqi

AU - McNair, Robert

AU - Wengraf, Joshua

AU - Robinson, Benjamin

AU - Kolosov, Oleg V.

N1 - This is an author-created, un-copyedited version of an article accepted for publication/published in Nanotechnology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.1088/1361-6528/ab9e27

PY - 2020/7/17

Y1 - 2020/7/17

N2 - Graphene's (GR) remarkable mechanical and electrical properties - such as its Young's modulus, lowmass per unit area, natural atomic flatness and electrical conductance - would make it an ideal material for micro and nanoelectromechanical systems (MEMS and NEMS). However, the difficulty of attaching GR to supports coupled with naturally occurring internal defects in a few layer GR can significantly adversely affect the performance of such devices. Here, we have used a combined contact resonance atomic force microscopy (CR-AFM) and ultrasonic force microscopy (UFM) approach to characterise and map with nanoscale spatial resolution GR membrane properties inaccessible to most conventional scanning probe characterisation techniques. Using a multi-layer GR plate (membrane) suspended over a round hole we show that this combined approach allows access to the mechanical properties, internal structure and attachment geometry of the membrane providing information about both the supported and suspended regions of the system. We show that UFM allows the precise geometrical position of the supported membrane-substrate contact to be located and provides indication of the local variation of its quality in the contact areas. At the same time, we show that by mapping the position sensitive frequency and phase response of CR-AFM response, one can reliably quantify the membrane stiffness, and image the defects in the suspended area of the membrane. The phase and amplitude of experimental CR-AFM measurements show excellent agreement with an analytical model accounting for the resonance of the combined CR-AFM probe-membrane system. The combination of UFM and CR-AFM provide an beneficial combination for investigation of few-layer NEMS systems based on two dimensional materials.

AB - Graphene's (GR) remarkable mechanical and electrical properties - such as its Young's modulus, lowmass per unit area, natural atomic flatness and electrical conductance - would make it an ideal material for micro and nanoelectromechanical systems (MEMS and NEMS). However, the difficulty of attaching GR to supports coupled with naturally occurring internal defects in a few layer GR can significantly adversely affect the performance of such devices. Here, we have used a combined contact resonance atomic force microscopy (CR-AFM) and ultrasonic force microscopy (UFM) approach to characterise and map with nanoscale spatial resolution GR membrane properties inaccessible to most conventional scanning probe characterisation techniques. Using a multi-layer GR plate (membrane) suspended over a round hole we show that this combined approach allows access to the mechanical properties, internal structure and attachment geometry of the membrane providing information about both the supported and suspended regions of the system. We show that UFM allows the precise geometrical position of the supported membrane-substrate contact to be located and provides indication of the local variation of its quality in the contact areas. At the same time, we show that by mapping the position sensitive frequency and phase response of CR-AFM response, one can reliably quantify the membrane stiffness, and image the defects in the suspended area of the membrane. The phase and amplitude of experimental CR-AFM measurements show excellent agreement with an analytical model accounting for the resonance of the combined CR-AFM probe-membrane system. The combination of UFM and CR-AFM provide an beneficial combination for investigation of few-layer NEMS systems based on two dimensional materials.

KW - UFM

KW - ultrasonic force microscopy

KW - contact resonance atomic force microscopy

KW - CR-AFM

KW - QEMS

KW - NEMS

KW - graphene

KW - 2D materials

KW - nanomechanics

KW - AFM • diffraction limit • FTIR spectroscopy

U2 - 10.1088/1361-6528/ab9e27

DO - 10.1088/1361-6528/ab9e27

M3 - Journal article

VL - 31

JO - Nanotechnology

JF - Nanotechnology

SN - 0957-4484

IS - 41

M1 - 415702

ER -