Lateral Graphene–hBCN Heterostructures as a Platform for Fully Two-Dimensional Transistors

Fiori, Gianluca; Betti, A.; Bruzzone, Samantha; Iannaccone, Giuseppe

doi:10.1021/nn300019b

Cited by 137 publications

(97 citation statements)

References 13 publications

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“…, [ 24,25 ] giving a LUMO level for the QDs that lies above the Dirac point of graphene, as shown schematically in Figure 4 a. When the QDs come into contact with graphene, the electronic charge will redistribute itself to bring the chemical potentials in the component layers into equilibrium.…”

Section: Lumomentioning

confidence: 99%

Ligand‐Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene–Quantum Dot Transistor

Turyanska

Makarovsky

Svatek

et al. 2015

Adv Elect Materials

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concentration can be modifi ed, and photoresponsivity of SLG can be signifi cantly enhanced by the choice of ligands. By reducing the length of capping ligands, hence the thickness of the dielectric barrier between the QDs and the SLG, and by preserving the integrity of the ligand layer, we achieve the efficient transfer of photogenerated carriers from the QDs to the graphene before recombining, resulting in enhanced photoresponsivities of up to ≈10 9 A W −1 .Single layer graphene grown by low-pressure chemical vapor deposition (LP-CVD) [ 14,15 ] was processed into a planar transistor and deposited onto a SiO 2 /n-Si substrate with oxide layer thickness t = 300 nm, as shown schematically in Figure 1 a (see also the Supporting Information, Figure S1). The length, L , and width, w , of the graphene channel are 6 and 10 µm, respectively. The n-Si layer serves as a gate electrode. Colloidal quantum dots with an average PbS core diameter of d = 4.5nm QD (Figure 1 b) were stabilized using the following capping ligands of different length, l , which determines the effective separation between the PbS nanocrystals and graphene: polyethylene glycol H (O CH 2 CH 2 ) n OH with n = 2000 for QD p2000 and n = 500 for QD p500 [ 16 ] and corresponding length of l ≈ 10 nm and l ≈ 5 nm, respectively; [ 17 ] a mixture of thioglycerol (TGL) and 2,3-dimercapto-1-propanol (DTG), l ≈ 0.5 nm for QD TGL , [ 18 ] see Table 1 . We note that the ligand size is estimated for extended molecules and does not include any effects that could arise from compression of the ligand layer upon drying under vacuum. The interparticle distances observed on TEM images are comparable with the theoretical estimate of the ligand length (see the Supporting Information, Figure S2). The QDs were dropcast from aqueous solution (5 mg mL −1 ) to produce continuous thick (>100 nm) coverage of the graphene layer, followed by drying for 12 h in vacuum at room temperature. The size of the QDs and their room temperature photoluminescence spectra (with a peak at photon energy ≈1.1eV) are similar in all three structures, i.e., they are not affected by the ligand. All measured devices demonstrate stable and reproducible behavior during the measurement period of at least 14 days. All samples were stored in dry nitrogen cabinet and all electrical measurements were performed at room temperature T = 300 K in vacuum (≈10 −6 mbar). The I V ( ) g characteristics were measured using slow sweeping rate, r , of the gate voltage, i.e., r ≤ 0.02 V s −1 .The pristine monolayer graphene devices show a linear dependence of current, I , on bias voltage, V s , and a minimum conductance at a gate voltage, V ≈ +30V g min corresponding to p-type doping with hole concentration, p ≈ 2 × 10 12 cm −2

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Section: Lumomentioning

confidence: 99%

Ligand‐Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene–Quantum Dot Transistor

Turyanska

Makarovsky

Svatek

et al. 2015

Adv Elect Materials

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“…Theoretical proposals based on the h-BNC structure include antiferromagnetism, 10 unique thermal transport phenomena, 11 and a lateral tunneling FET. 12 The h-BNC layer was first fabricated on Cu foil using a thermal catalytic chemical vapor deposition (CVD) process, where methane (CH4) and ammonia borane (NH3-BH3) molecules were used as precursors for carbon and boron nitride. 6 Afterward, the domain sizes of graphene and h-BN were successfully controlled.…”

Section: Introductionmentioning

confidence: 99%

Epitaxial Growth of a Single-Crystal Hybridized Boron Nitride and Graphene Layer on a Wide-Band Gap Semiconductor

et al. 2015

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Vertical and lateral heterogeneous structures of two-dimensional (2D) materials have paved the way for pioneering studies on the physics and applications of 2D materials. A hybridized hexagonal boron nitride (h-BN) and graphene lateral structure, a heterogeneous 2D structure, has been fabricated on single-crystal metals or metal foils by chemical vapor deposition (CVD).However, once fabricated on metals, the h-BN/graphene lateral structures require an additional transfer process for device applications, as reported for CVD graphene grown on metal foils. Here, we demonstrate that a single-crystal h-BN/graphene lateral structure can be epitaxially grown on a wide-gap semiconductor, SiC(0001). First, a single-crystal h-BN layer with the same orientation as bulk SiC was grown on a Si-terminated SiC substrate at 850 ℃ using borazine molecules.Second, when heated above 1150 ℃ in vacuum, the h-BN layer was partially removed and, subsequently, replaced with graphene domains. Interestingly, these graphene domains possess the same orientation as the h-BN layer, resulting in a single-crystal h-BN/graphene lateral structure on a whole sample area. For temperatures above 1600 ℃ , the single-crystal h-BN layer was completely replaced by the single-crystal graphene layer. The crystalline structure, electronic band structure, and atomic structure of the h-BN/graphene lateral structure were studied by using low energy electron diffraction, angle-resolved photoemission spectroscopy, and scanning tunneling microscopy, respectively. The h-BN/graphene lateral structure fabricated on a wide-gap semiconductor substrate can be directly applied to devices without a further transfer process, as reported for epitaxial graphene on a SiC substrate.

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“…15 This kind of bi-phase hybrid systems with semiconducting and metallic regions paved the way to design the new generation 2D photoelectric devices based on the in-plane metal/semiconductor heterostructures. 16,17 Compared with the comprehensive studies on the fabrications [18][19][20][21] and applications 22,23 of graphene/h-BN heterostructures, few reports focused on the in-plane 1T/2H MoS2 hybrid systems. [14][15][16] By using lithium based chemical exfoliation method, Eda et al 15 firstly synthetized a single layer of exfoliated MoS 2 consisting of both 2H and 1T phases then form chemically homogeneous atomic and electronic heterostructures with potential for novel molecular functionalities.…”

Section: Introductionmentioning

confidence: 99%

Structural, mechanical and electronic properties of in-plane 1T/2H phase interface of MoS2 heterostructures

et al. 2015

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Two-dimensional (2D) molybdenum disulfide (MoS2) phase hybrid system composed by 2H and 1T phase is a natural metal/semiconductor heterostructures and promised a wide range of potential applications. Here, we report the first principle investigations on the structural, mechanical and electronic properties of hybrid system with armchair (AC) and zigzag (ZZ) interfaces. The ZZ type 1T/2H interface are more energy favorable than AC type interface with 3.39 eV/nm. Similar with that of bulked 1T MoS2, the intrinsic strengths of the heterostructures are lower than that of the bulk 2H, especially for that with ZZ interface. Analysis of density of states shows that the electronic properties gradually transmitted from the metallic 1T phase to the semiconducting 2H phase for the structural abrupt interface. The present theoretical results constitute a useful picture for the 2D electronic devices using current MoS2 1T/2H heterostructures and provide vital insights into the other 2D hybrid materials.

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Lateral Graphene–hBCN Heterostructures as a Platform for Fully Two-Dimensional Transistors

Cited by 137 publications

References 13 publications

Ligand‐Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene–Quantum Dot Transistor

Ligand‐Induced Control of Photoconductive Gain and Doping in a Hybrid Graphene–Quantum Dot Transistor

Epitaxial Growth of a Single-Crystal Hybridized Boron Nitride and Graphene Layer on a Wide-Band Gap Semiconductor

Structural, mechanical and electronic properties of in-plane 1T/2H phase interface of MoS2 heterostructures

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