  Room temperature growth of two-dimensional van der Waals (2D-vdW) materials
is indispensable for state-of-the-art nanotechnology. The low temperature
growth supersedes the requirement of elevated growth temperature accompanied
with high thermal budgets. Moreover, for electronic applications, low or room
temperature growth reduces the possibility of intrinsic film-substrate
interfacial thermal diffusion related deterioration of functional properties
and consequent device performance. Here, we demonstrated the growth of
ultrawide-bandgap boron nitride (BN) at room temperature by using the pulsed
laser deposition (PLD) process and demonstrated various functionalities for
potential applications. Comprehensive chemical, spectroscopic and microscopic
characterization confirms the growth of ordered nanosheet-like hexagonal BN.
Functionally, nanosheets show hydrophobicity, high lubricity (low coefficient
of friction), low refractive index within the visible to near-infrared
wavelength range, and room temperature single-photon quantum emission. Our work
unveils an important step that brings a plethora of applications potential for
room temperature grown h-BN nanosheets as it can be feasible on any given
substrate, thus creating a scenario for h-BN on demand at frugal thermal
budget.
