Low-Temperature
Synthesis of Boron Nitride as a Large-Scale
Passivation and Protection Layer for Two-Dimensional Materials and
High-Performance Devices
Two-dimensional
materials (2DMs) with extraordinary electronic
and optical properties have attracted great interest in optoelectronic
applications. Due to their atomically thin feature, 2DM-based devices
are generally sensitive to oxygen and moisture in ambient air, and
thus, practical application of durable 2DM-based devices remains challenging.
Here, we report a novel strategy to directly synthesize amorphous
BN film on various 2DMs and field-effect transistor (FET) devices
at low temperatures by conventional chemical vapor deposition. The
wafer-scale BN film with controllable thickness serves as a passivation
and heat dissipation layer, further improving the long-term stability,
the resistance to laser irradiation, and the antioxidation performance
of the underneath 2DMs. In particular, the BN capping layer could
be deposited directly on a WSe2 FET at low temperature
to achieve a clean and conformal interface. The high performance of
the BN-capped WSe2 device is realized with suppressed current
fluctuations and 10-fold enhanced carrier mobility. The transfer-free
amorphous BN synthesis technique is simple and applicable to various
2DMs grown on arbitrary substrates, which shows great potential for
applications in future two-dimensional electronics.