Table 1.

The main preparation methods and comparison of phosphorene at present

Method		Experiment	Thickness	Carrier mobility (cm2 V−1 s−1)	Characteristic	References
Top-down	Mechanical exfoliation	Scotch tape-based mechanical exfoliation	4 ~ 6 nm	286	Long time consuming, low yield, uncontrolled size	[44]
		metal-assisted mechanical exfoliation	~4 nm	68.6	long time consuming, low yield, uncontrolled size, ~ 50 µm lateral dimension	[45]
	Liquid-phase exfoliation	Sonic exfoliated in NMP for 24 h	3–5 layers	–	200 × 200 nm2 lateral dimension	[51]
		Sonic exfoliated in formamide, and centrifuged at 9000 rpm	3 ± 1 layers	–	50–300 nm lateral dimension, 38% yield	[57]
		Phytic acid-assisted exfoliation in DMF	6–8 layers	–	Several tens of micrometers lateral dimension	[59]
		Microwave-assisted exfoliation in NMP	4–11 layers	–	Hundreds of nanometers up to ≈ 4 µm lateral dimension, < 12 min processing time	[60]
	Electrochemical exfoliation	Two-electrode system (Pt and bulk BP), electrolyte (0.05 M Na2SO4), +7 V voltage	3–15 layers	7.3	0.5 to 30 µm lateral dimension, yield excess 80%, non-uniform size	[64]
		Two-electrode system (Pt and bulk BP), electrolyte (0.001 M TAA in DMSO), − 5 V voltage	~5 layers	100	∼10 μm2 lateral dimension, several minutes processing time, > 80% yield	[65]
Bottom-up	CVD	Conversion of RP film to BP film by CVD	~4 layers	–	Controllable size, a variety of lateral size samples	[72]
	PLD	Deposited BP film at 150 °C by PLD	2–8 nm	14	Low processing temperature, tunable direct band gap	[74]
	Gas-phase growth strategy	BP is grown directly on the insulating silicon substrates	A few to hundreds of nanometers	1200	Controllable thickness and lateral dimension can up to millimeters	[75]