Methods for preparing a monolayer or few-layer crystalline black phosphorous film on a two-dimensional surface by focusing a pulsed laser beam on a black phosphorous target

A method for preparing a few-layer crystalline black phosphorus film, the method comprising:

• a. positioning a [KMg3(AlSi3O10)F2 substrate in a process chamber, wherein the [KMg3(AlSi3O10)F2 substrate comprises a deposition surface;
• b. positioning a black phosphorus single crystal target in the process chamber between 30-40 mm from the [KMg3(AlSi3O10)F2 substrate;
• and
• c. focusing a pulsed laser beam having a laser fluency between 1.0-1.5 J/cm2 on the black phosphorus single crystal target to ablate the black phosphorous single crystal target thereby forming a plume comprising phosphorus plasma directed towards the deposition surface thereby forming the few-layer crystalline black phosphorus film, wherein the few-layer crystalline black phosphorus film is between 2-6 layers thick and comprises a single crystalline region over at least 90% of an area of 1 cm2, and wherein the pressure of the process chamber is maintained between 1.0×10−10 Torr and 1.0×10−8 Torr.