Fabrication of CVD graphene-based devices via laser ablation for wafer-scale characterization

Mackenzie, David; Buron, Jonas Christian Due; Whelan, Patrick Rebsdorf; Jessen, Bjarke S.; Silajdźić, Adnan; Pesquera, Amaia; Centeno, Alba; Zurutuza, Amaia; Bøggild, Peter; Petersen, Dirch Hjorth

doi:10.1088/2053-1583/2/4/045003

Cited by 38 publications

(38 citation statements)

References 22 publications

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“…Temperature dependent electrical transport measurements were conducted using a Lakeshore low-temperature measurement system (CRX-4K) and Linkam probe station under vacuum and nitrogen ambient conditions. 43 The sample was heated by heating the chuck (on which it was placed) and not the entire chamber. Further, the nitrogen gas was flowing continuously between inlet and outlet line of the chamber which assures that nitrogen gas is not at the same temperature as that of the sample, rather it is closer to room temperature.…”

Section: Methodsmentioning

confidence: 99%

Reversible hysteresis inversion in MoS2 field effect transistors

et al. 2017

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The origin of threshold voltage instability with gate voltage in MoS 2 transistors is poorly understood but critical for device reliability and performance. Reversibility of the temperature dependence of hysteresis and its inversion with temperature in MoS 2 transistors has not been demonstrated. In this work, we delineate two independent mechanisms responsible for thermally assisted hysteresis inversion in gate transfer characteristics of contact resistance-independent multilayer MoS 2 transistors. Variable temperature hysteresis measurements were performed on gated four-terminal van der Pauw and two-terminal devices of MoS 2 on SiO 2 . Additional hysteresis measurements on suspended (~100 nm air gap between MoS 2 and SiO 2 ) transistors and under different ambient conditions (vacuum/nitrogen) were used to further isolate the mechanisms. Clockwise hysteresis at room temperature (300 K) that decreases with increasing temperature is shown to result from intrinsic defects/traps in MoS 2 . At higher temperatures a second, independent mechanism of charge trapping and de-trapping between the oxide and p + Si gate leads to hysteresis collapse at~350 K and anti-clockwise hysteresis (inversion) for temperatures >350 K. The intrinsic-oxide trap model has been corroborated through device simulations. Further, pulsed current-voltage (I-V) measurements were carried out to extract the trap time constants at different temperatures. Non-volatile memory and temperature sensor applications exploiting temperature dependent hysteresis inversion and its reversibility in MoS 2 transistors have also been demonstrated. npj 2D Materials and Applications (2017) 1:34 ; doi:10.1038/s41699-017-0038-y INTRODUCTION Among two-dimensional materials, graphene 1,2 was the first to be isolated and studied with respect to electronic applications. Due to lack of an energy bandgap in graphene, other 2D materials such as layered transition metal dichalcogenides (TMDs) comprising a wide selection of materials with different bandstructures, and therefore different electrical and optical properties, have garnered significant attention.3-5 Molybdenum disulfide (MoS 2 ) has emerged as a prospective candidate for transistor applications. The presence of a direct bandgap (~1.8 eV) in monolayer form and an indirect bandgap (~1.2 eV) in multilayer MoS 2 makes it a promising channel material for field effect transistors (FETs).

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Section: Methodsmentioning

confidence: 99%

Reversible hysteresis inversion in MoS2 field effect transistors

et al. 2017

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“…1(d), Ti/Au contacts were deposited onto the graphene film subsequent to THz-TDS analysis, by electron beam evaporation through an aluminum shadow mask. The graphene film was patterned by picosecond laser ablation into 5 mm wide square van der Pauw (vdP) devices, suitable for dual-configuration sheet conductance and Hall effect measurements to extract carrier mobility and carrier density [19]. Dual configuration measurements suppress geometrical errors in both sheet conductance [20] and Hall effect measurements [21] and allow the electrical continuity to be determined [13,18,22,23].…”

Section: Van Der Pauw Device Fabrication and Hall Measurementsmentioning

confidence: 99%

Terahertz wafer-scale mobility mapping of graphene on insulating substrates without a gate

Buron¹,

Mackenzie²,

Petersen³

et al. 2015

Opt. Express

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(2015). Terahertz wafer-scale mobility mapping of graphene on insulating substrates without a gate. Optics Express, 23(24) maps with a 400 µm step size. σ dc -and τ sc -maps are translated into µ drift and N s maps through Boltzmann transport theory for graphene charge carriers and these parameters are directly compared to van der Pauw device measurements on the same wafer. The technique is compatible with all substrate materials that exhibit a reasonably low absorption coefficient for terahertz radiation. This includes many materials used for transferring CVD graphene in production facilities as well as in envisioned products, such as polymer films, glass substrates, cloth, or paper substrates.

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“…For friction welding, the low efficiency and welding defects are concerning. Alternatively, highpower-density laser has attracted enormous research interest and found its wide application in a broad branch of manufacturing areas including selective laser sintering and three-dimensional printing [1][2][3][4][5][6], surface nanostructuring [7][8][9][10][11][12], multimaterial joining and integration [13][14][15][16][17], material removal [18,19], and mechanical/optical property enhancements [20][21][22][23]. Characteristics, such as contact-free processing, good flexibility and tunablity, high efficiency, and throughput, make laser a feasible route for welding of 42CrMo [24,25].…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

et al. 2016

Int J Adv Manuf Technol

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Laser keyhole welding of 42CrMo in air and argon atmospheres has been studied both experimentally and numerically. Significant macroscale difference is observed for welding carried out under argon and air shielding. Fusion zone of welding under argon shielding has a "▽" shape, while it has a "U" shape for welding in air. The surface of the weldment is smoother for welding in argon when compared with that in air. Oxygen effect is proposed to account for the experimental results. A three-dimensional heat transfer model with a predefined keyhole is developed to study the heat transport and fluid flow in laser welding process. The variation of weld pool geometry and temperature history is investigated for different oxygen concentrations. It is found that a small amount of oxygen could significantly modify the weld pool dimension, while keeping the temperature history of materials, and thus the microstructure, in the fusion zone and heat-affected zone unchanged.

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Fabrication of CVD graphene-based devices via laser ablation for wafer-scale characterization

Cited by 38 publications

References 22 publications

Reversible hysteresis inversion in MoS2 field effect transistors

Reversible hysteresis inversion in MoS2 field effect transistors

Terahertz wafer-scale mobility mapping of graphene on insulating substrates without a gate

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

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