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Temperature-triggered chemical switching growth of in-plane and vertically stacked graphene-boron nitride heterostructures.

Gao T, Song X, Du H, Nie Y, Chen Y, Ji Q, Sun J, Yang Y, Zhang Y, Liu Z - Nat Commun (2015)

Bottom Line: Here, via chemical vapour deposition and using benzoic acid precursor, we have achieved the selective growth of h-BN-G and G/h-BN through a temperature-triggered switching reaction.The present work demonstrates the chemical designability of growth process for controlled synthesis of graphene and h-BN heterostructures.With practical scalability, high uniformity and quality, our approach will promote the development of graphene-based electronics and optoelectronics.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Low-Dimensional Carbon Materials, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

ABSTRACT
In-plane and vertically stacked heterostructures of graphene and hexagonal boron nitride (h-BN-G and G/h-BN, respectively) are both recent focuses of graphene research. However, targeted synthesis of either heterostructure remains a challenge. Here, via chemical vapour deposition and using benzoic acid precursor, we have achieved the selective growth of h-BN-G and G/h-BN through a temperature-triggered switching reaction. The perfect in-plane h-BN-G is characterized by scanning tunnelling microscopy (STM), showing atomically patched graphene and h-BN with typical zigzag edges. In contrast, the vertical alignment of G/h-BN is confirmed by unique lattice-mismatch-induced moiré patterns in high-resolution STM images, and two sets of aligned selected area electron diffraction spots, both suggesting a van der Waals epitaxial mechanism. The present work demonstrates the chemical designability of growth process for controlled synthesis of graphene and h-BN heterostructures. With practical scalability, high uniformity and quality, our approach will promote the development of graphene-based electronics and optoelectronics.

No MeSH data available.


Related in: MedlinePlus

Differences in surface potential and work function between h-BN-G and G/h-BN.AFM height (a) and amplitude (b) images and EFM surface potential image (c) for h-BN-G on Cu foils, showing contrast for graphene regions, as marked by hexagonal shapes. Similarly, AFM height (d) and amplitude (e) images and EFM surface potential (f) image for G/h-BN on Cu foils, showing minor differences between graphene and h-BN regions. (g) Schematic diagram of the EFM measurement. (h,i) EFM phase plotted as a function of tip bias voltage for graphene (red) and BN (blue) in h-BN-G and G/h-BN, respectively. The scale bars in a–f are 2 μm.
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f3: Differences in surface potential and work function between h-BN-G and G/h-BN.AFM height (a) and amplitude (b) images and EFM surface potential image (c) for h-BN-G on Cu foils, showing contrast for graphene regions, as marked by hexagonal shapes. Similarly, AFM height (d) and amplitude (e) images and EFM surface potential (f) image for G/h-BN on Cu foils, showing minor differences between graphene and h-BN regions. (g) Schematic diagram of the EFM measurement. (h,i) EFM phase plotted as a function of tip bias voltage for graphene (red) and BN (blue) in h-BN-G and G/h-BN, respectively. The scale bars in a–f are 2 μm.

Mentions: Electrostatic force microscopy (EFM) has been proven effective to evaluate the layer number of 2D materials3738. By measuring the surface potential or work function, we may distinguish the in-plane h-BN-G from stacked G/h-BN and understand the details of interfacial charge transfer. In EFM measurements, two-pass lift mode was used with 0.1 V bias voltage applied between a conductive AFM tip and the sample. Figure 3a–c show the AFM height, amplitude and EFM surface potential images, respectively, of h-BN-G on Cu foils. Notably, graphene regions (labelled by light blue lines in Fig. 3b) are more corrugated than the surrounding h-BN. Similar phenomenon has been reported by Han et al.15 and Cho et al.39, which was attributed to the different thermal expansion effects of graphene, h-BN and Cu substrate. As seen from the surface potential image shown in Fig. 3c, the embedded graphene islands can be clearly distinguished from the surrounding h-BN. In this case, the surface potential of graphene region is ∼80 meV lower than that of h-BN. The situation for stacked G/h-BN film is highly different as shown in Fig. 3d–f. The graphene area exhibits only ∼20 meV decrease in surface potential as compared with that of the h-BN area. Note that the surface potential in EFM measurements (Fig. 3g) reflects the local surface charge distribution when a bias voltage is applied between the EFM probe and the sample. In the case of G/h-BN film, the presence of dielectric h-BN layer between graphene and Cu substrate will certainly screen the charging effect from Cu substrate, leading to smaller surface potential difference between the two kinds of regions (G/h-BN/Cu and h-BN/Cu) than that of a h-BN-G film (h-BN/Cu and G/Cu).


Temperature-triggered chemical switching growth of in-plane and vertically stacked graphene-boron nitride heterostructures.

Gao T, Song X, Du H, Nie Y, Chen Y, Ji Q, Sun J, Yang Y, Zhang Y, Liu Z - Nat Commun (2015)

Differences in surface potential and work function between h-BN-G and G/h-BN.AFM height (a) and amplitude (b) images and EFM surface potential image (c) for h-BN-G on Cu foils, showing contrast for graphene regions, as marked by hexagonal shapes. Similarly, AFM height (d) and amplitude (e) images and EFM surface potential (f) image for G/h-BN on Cu foils, showing minor differences between graphene and h-BN regions. (g) Schematic diagram of the EFM measurement. (h,i) EFM phase plotted as a function of tip bias voltage for graphene (red) and BN (blue) in h-BN-G and G/h-BN, respectively. The scale bars in a–f are 2 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403442&req=5

f3: Differences in surface potential and work function between h-BN-G and G/h-BN.AFM height (a) and amplitude (b) images and EFM surface potential image (c) for h-BN-G on Cu foils, showing contrast for graphene regions, as marked by hexagonal shapes. Similarly, AFM height (d) and amplitude (e) images and EFM surface potential (f) image for G/h-BN on Cu foils, showing minor differences between graphene and h-BN regions. (g) Schematic diagram of the EFM measurement. (h,i) EFM phase plotted as a function of tip bias voltage for graphene (red) and BN (blue) in h-BN-G and G/h-BN, respectively. The scale bars in a–f are 2 μm.
Mentions: Electrostatic force microscopy (EFM) has been proven effective to evaluate the layer number of 2D materials3738. By measuring the surface potential or work function, we may distinguish the in-plane h-BN-G from stacked G/h-BN and understand the details of interfacial charge transfer. In EFM measurements, two-pass lift mode was used with 0.1 V bias voltage applied between a conductive AFM tip and the sample. Figure 3a–c show the AFM height, amplitude and EFM surface potential images, respectively, of h-BN-G on Cu foils. Notably, graphene regions (labelled by light blue lines in Fig. 3b) are more corrugated than the surrounding h-BN. Similar phenomenon has been reported by Han et al.15 and Cho et al.39, which was attributed to the different thermal expansion effects of graphene, h-BN and Cu substrate. As seen from the surface potential image shown in Fig. 3c, the embedded graphene islands can be clearly distinguished from the surrounding h-BN. In this case, the surface potential of graphene region is ∼80 meV lower than that of h-BN. The situation for stacked G/h-BN film is highly different as shown in Fig. 3d–f. The graphene area exhibits only ∼20 meV decrease in surface potential as compared with that of the h-BN area. Note that the surface potential in EFM measurements (Fig. 3g) reflects the local surface charge distribution when a bias voltage is applied between the EFM probe and the sample. In the case of G/h-BN film, the presence of dielectric h-BN layer between graphene and Cu substrate will certainly screen the charging effect from Cu substrate, leading to smaller surface potential difference between the two kinds of regions (G/h-BN/Cu and h-BN/Cu) than that of a h-BN-G film (h-BN/Cu and G/Cu).

Bottom Line: Here, via chemical vapour deposition and using benzoic acid precursor, we have achieved the selective growth of h-BN-G and G/h-BN through a temperature-triggered switching reaction.The present work demonstrates the chemical designability of growth process for controlled synthesis of graphene and h-BN heterostructures.With practical scalability, high uniformity and quality, our approach will promote the development of graphene-based electronics and optoelectronics.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Low-Dimensional Carbon Materials, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

ABSTRACT
In-plane and vertically stacked heterostructures of graphene and hexagonal boron nitride (h-BN-G and G/h-BN, respectively) are both recent focuses of graphene research. However, targeted synthesis of either heterostructure remains a challenge. Here, via chemical vapour deposition and using benzoic acid precursor, we have achieved the selective growth of h-BN-G and G/h-BN through a temperature-triggered switching reaction. The perfect in-plane h-BN-G is characterized by scanning tunnelling microscopy (STM), showing atomically patched graphene and h-BN with typical zigzag edges. In contrast, the vertical alignment of G/h-BN is confirmed by unique lattice-mismatch-induced moiré patterns in high-resolution STM images, and two sets of aligned selected area electron diffraction spots, both suggesting a van der Waals epitaxial mechanism. The present work demonstrates the chemical designability of growth process for controlled synthesis of graphene and h-BN heterostructures. With practical scalability, high uniformity and quality, our approach will promote the development of graphene-based electronics and optoelectronics.

No MeSH data available.


Related in: MedlinePlus