Owing to the distinctively morphological and structural features, vertically-aligned graphene nanosheets (VGs) possess many unique properties and hold great promise for applications in various fields. For controllable preparation and wide application of VGs, the establishing reliable growth method and profound understanding of the growth mechanism are of vital significance. Up to date, VGs are normally produced by plasma-enhanced chemical vapor deposition (PECVD) and it's considered that plasma is an indispensible factor for the vertical alignment of graphene sheets. Herein, for the first time, we report the facile and controllable VGs growth via a thermal CVD by precisely tuning growth parameters. Experimental observations in combination with detailed energy calculations reveal that the flow rate of carbon precursor determines the growth dynamics of graphene in CVD. This work offers a novel and reliable technique for VGs preparation and provides new insights into the intrinsic mechanism of vertical graphene growth. Furthermore, benefiting from the ultra-high density of edge sites, thin thickness, and outstanding electrical conductivity of VGs, the as-prepared VGs exhibit excellent field-emission performance such as ultra-low turn-on electric field and threshold field down to 1.07 and 1.65 V μm⁻¹, respectively.

中文翻译：

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通过热CVD容易地生长垂直排列的石墨烯纳米片：实验和理论研究

由于其独特的形态和结构特征，垂直排列的石墨烯纳米片（VG）具有许多独特的特性，并有望在各个领域中得到应用。为了可控的制备和广泛应用VG，建立可靠的生长方法和深刻理解生长机理具有至关重要的意义。迄今为止，VG通常是通过等离子体增强化学气相沉积（PECVD）产生的，并且认为等离子体是石墨烯片垂直排列必不可少的因素。在此，我们首次通过精确调整生长参数，通过热CVD报告了可控且可控的VG生长。实验观察结合详细的能量计算表明，碳前体的流速决定了CVD中石墨烯的生长动力学。这项工作为VG的制备提供了一种新颖而可靠的技术，并为垂直石墨烯生长的内在机理提供了新的见解。此外，得益于VG的边缘部位的超高密度，薄的厚度和出色的导电性，所制备的VG表现出出色的场发射性能，例如超低的开启电场和低至1.07的阈值场和1.65 Vμm^-1。