Abstract
The direct growth of high-quality, large single-crystalline domains of graphene on a dielectric substrate is of vital importance for applications in electronics and optoelectronics. Traditionally, graphene domains grown on dielectrics are typically only ~1 μm with a growth rate of ~1 nm min−1 or less, the main reason is the lack of a catalyst. Here we show that silane, serving as a gaseous catalyst, is able to boost the graphene growth rate to ~1 μm min−1, thereby promoting graphene domains up to 20 μm in size to be synthesized via chemical vapour deposition (CVD) on hexagonal boron nitride (h-BN). Hall measurements show that the mobility of the sample reaches 20,000 cm2 V−1 s−1 at room temperature, which is among the best for CVD-grown graphene. Combining the advantages of both catalytic CVD and the ultra-flat dielectric substrate, gaseous catalyst-assisted CVD paves the way for synthesizing high-quality graphene for device applications while avoiding the transfer process.
Highlights
The direct growth of high-quality, large single-crystalline domains of graphene on a dielectric substrate is of vital importance for applications in electronics and optoelectronics
It is found that the growth rate of graphene in the absence of a catalyst is about 5 nm min À 1, which increases by an order of magnitude to 50 nm min À 1 when germane is introduced
The growth rate further increases to 400 nm min À 1 and, if the substrate is further heated to 1,350 °C, the growth rate reaches B1,000 nm min À 1, which is very close to that of graphene grown on a metal surface by chemical vapour deposition (CVD) (Fig. 1b)
Summary
The direct growth of high-quality, large single-crystalline domains of graphene on a dielectric substrate is of vital importance for applications in electronics and optoelectronics. Growing graphene directly on ultra-flat h-BN can greatly preserve the pristine properties of graphene, and the mobility of the aligned graphene grown on h-BN via the CVD method reaches 20,000–30,000 cm[2] V À 1 s À 1 at room temperature[22] This growth method suffers from the great drawback of very low growth rate (B1 nm min À 1) and the generation of domain sizes that are mostly smaller than 1 mm. The introduction of the gaseous catalyst effectively improves the percentage of precisely aligned domains on h-BN These results present a promising route towards very high-quality, transfer-free graphene on dielectric substrates for electronic applications
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