Abstract
Silicon carbide (SiC) has already found useful applications in high-power electronic devices and light-emitting diodes (LEDs). Interestingly, SiC is a suitable substrate for growing monolayer epitaxial graphene and GaN-based devices. Therefore, it provides the opportunity for integration of high-power devices, LEDs, atomically thin electronics, and high-frequency devices, all of which can be prepared on the same SiC substrate. In this paper, we concentrate on detailed measurements on ultralow-density p-type monolayer epitaxial graphene, which has yet to be extensively studied. The measured resistivity ρxx shows insulating behavior in the sense that ρxx decreases with increasing temperature T over a wide range of T (1.5 K ≤ T ≤ 300 K). The crossover from negative magnetoresistivity (MR) to positive magnetoresistivity at T = 40 K in the low-field regime is ascribed to a transition from low-T quantum transport to high-T classical transport. For T ≥ 120 K, the measured positive MR ratio [ρxx(B) − ρxx(B = 0)]/ρxx(B = 0) at B = 2 T decreases with increasing T, but the positive MR persists up to room temperature. Our experimental results suggest that the large MR ratio (~100% at B = 9 T) is an intrinsic property of ultralow-charge-density graphene, regardless of the carrier type. This effect may find applications in magnetic sensors and magnetoresistance devices.
Highlights
Silicon carbide (SiC) is an extremely useful semiconductor material which has already found applications in light-emitting diodes (LEDs) [1], detectors [2], and power devices [3] that operate at high temperatures and/or high voltages
Graphene prepared by chemical vapor deposition (CVD) [11,12,13] can be of meter-size, yet the subsequent transfer required for device fabrication may introduce undesired polymer residues and wrinkles, which may compromise
We have shown that, for example, using the low-pressure gentle heating technique, we are able to remove air adsorbate on epitaxial graphene so that chemical doping can be tuned [44]
Summary
Silicon carbide (SiC) is an extremely useful semiconductor material which has already found applications in light-emitting diodes (LEDs) [1], detectors [2], and power devices [3] that operate at high temperatures and/or high voltages. GaN-based materials [4] and, most importantly, for preparing wafer-scale epitaxial graphene using the high-temperature sublimation technique [5]. It is possible to prepare low-dimensional graphene-based electronic devices [5] and high-power devices [3], LEDs [1], and GaN-based high-electron mobility transistors (HEMTs) [6] on the same SiC substrate. Graphene prepared by mechanical exfoliation is of high-quality [7,8,10], the limited size of the resulting flakes may be hindered in real-world applications. Graphene prepared by chemical vapor deposition (CVD) [11,12,13] can be of meter-size, yet the subsequent transfer required for device fabrication may introduce undesired polymer residues and wrinkles, which may compromise
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