Influence of the Total Gas Flow at Different Reaction Times for CVD-Graphene Synthesis on Polycrystalline Nickel

Table 2

Raman spectroscopy parameters and percentage of each type of graphene.

Total gas flow (NmL/min)	Type of graphene	%	/	/	FWHM	G Raman shift; (cm^−1)	2D Raman; shift; (cm^−1)	Thickness value
130	MONOLAYER	76.9	0.015	2.5	32	1580	2703	781
	BILAYER	11.4	0.016	1.4	47	1580	2699
	FEW-LAYER	11.6	0.006	0.6	63	1580	2707
	MULTILAYER	0.1	0.007	0.5	74	1581	2708
100	MONOLAYER	78.5	0.032	1.5	56	1581	2699	798
	BILAYER	11.4	0.002	1.0	58	1580	2703
	FEW-LAYER	9.9	0.002	0.5	69	1581	2711
	MULTILAYER	0.2	0.006	0.5	79	1580	2708
80	MONOLAYER	80.2	0.075	3.7	42	1580	2699	810
	BILAYER	8.4	0.019	2.1	47	1580	2714
	FEW-LAYER	11.1	0.005	0.5	71	1580	2713
	MULTILAYER	0.3	0.006	0.4	74	1580	2711

(Synthesis conditions: 980°C, 1 min reaction time, CH₄/H₂ = 0.07 v/v, and 80–130 NmL (CH₄ + H₂)/min).