  Outstanding wide-bandgap semiconductor material such as gallium nitride (GaN)
has been extensively utilized in power electronics, radiofrequency amplifiers,
and harsh environment devices. Due to its quantum confinement effect in
enabling desired deep-ultraviolet emission, excitonic impact, and electronic
transport features, two-dimensional (2D) or ultrathin quasi-2D GaN
semiconductors have been one of the most remarkable candidates for future
growth of microelectronic devices. Here, for the first time, we reported a
large area, wide bandgap, and room-temperature quasi-2D GaN synthesis and
printing strategy through introducing the plasma medicated liquid metal gallium
surface-confined nitridation reaction mechanism. The developed direct
fabrication and compositional process is consistent with various electronics
manufacturing approaches and thus opens an easy going way for cost-effective
growth of the third-generation semiconductor. In particular, the fully printed
field-effect transistors relying on the GaN thus made show p-type switching
with an on/off ratio greater than 105, maximum field-effect hole mobility of 53
cm2/(V*s), and a small sub-threshold swing. As it was demonstrated, the present
method allows to produce at room temperature the GaN with thickness spanning
from 1nm to nanometers. This basic method can be further extended, generalized,
and utilized for making various electronic and photoelectronic devices in the
coming time.
