Upscaling high-quality CVD graphene devices to 100 micron-scale and beyond

Abstract

We describe a method for transferring ultra large-scale CVD-grown graphene sheets. These samples can be fabricated as large as several cm 2 and are characterized by magneto-transport measurements on SiO 2 substrates. The process we have developed is highly effective and limits damage to the graphene all the way through metal liftoff, as shown in carrier mobility measurements and the observation of the quantum Hall effect. The charge-neutral point is shown to move drastically to near-zero gate voltage after a 2-step post-fabrication annealing process, which also allows for greatly diminished hysteresis.PACS numbers: 72.80.Vp, 81.05.ue.Graphene is well-known for its desirable electrical properties, 1 and with all of the intense focus on research in the material, new applications are being constantly discovered. While graphene is known to have its best electrical properties when it is single-crystalline and suspended, 2,3 those attributes are currently not feasible for mass-produced devices. There have been very exciting developments related to improving non-suspended graphene's mobility on more exotic substrates such as hBN, 4,5 as well as improving the chemical vapor deposition (CVD) growth process for producing better quality devices with large grain sizes. 5-7 However, these developments are currently difficult to scale up and automate.On the other hand, CVD-grown graphene is still the best way to repeatably produce large areas of monolayer graphene, and SiO 2 is a well-known substrate that is already integrated into many processes from semiconductor physics to MEMS, 8,9 and beyond. Previous work has shown how to transfer large areas of CVD-grown graphene onto arbitrary substrates 10-13 and remove contaminants. 10,14 However, previous CVD-grown graphene on SiO 2 devices do not combine the desirable properties of high enough quality electrical characteristics to display the quantum Hall effect (QHE), a charge neutral point (CNP) near zero gate voltage, and a large device size, with typical finished devices being on the order of 10 µm. 15 Large-scale integration of easily manufactured, high-quality graphene devices is desirable in many different applications, such as graphene transistors, broadband optical modulators 16 and THz antennas. 17 Challenges arise when fabricating high-quality CVDgrown graphene devices, primarily due to contaminants of all kinds easily attaching to graphene. With each step,

Dirac imprints on the g -factor anisotropy in graphene

“…However, under real experimental conditions and in a macroscopic graphene sample with a spin imbalance n ↑ − n ↓ = 0, the problem becomes many-body and corrections to the g-factor emerge. the graphene that was synthesized by chemical vapor deposition is described by Lyon et al [35]. We employed low temperature (1.4K) resistively-detected electron-spin resonance (RD-ESR) [12,36,37], a spin-selective probing technique that couples carriers of opposite spin by microwave excitation, and detects the response resistively.…”

Development, Processing and Applications of a UV-Curable Polymer with Surface Active Thiol Groups

“…A 200 μm by 20 μm Hall bar structure was patterned by standard optical lithography, O 2 plasma etching and PVD of Au for the Ohmic contacts. A detailed description of the fabrication process can be found in [ 25 ]. The device was then transferred to a ceramic chip carrier and wire-bonded using a combination of ultrasonic wedge bonding (for the chip carrier pads) and conductive silver paint (for the graphene contacts).…”

Giant acoustically-induced synthetic Hall voltages in graphene

“…The thickness of the dielectric layer is adjusted to the acoustic wave length and suppresses any leakage of the SAW into the bulk. CVD Monolayer graphene (MLG) is transferred to the substrate 22 and patterned into a Hall bar close to an IDT (sample details in the caption of Fig. 1).…”