  Semiconductor InSb nanosheet/hexagonal boron nitride (hBN)/graphite trilayers
are fabricated, and single- and double-gate devices made from the trilayers are
realized and characterized. The InSb nanosheets employed in the trilayer
devices are epitaxially grown, free-standing, zincblende crystals and are in
micrometer lateral sizes. The hBN and graphite flakes are obtained by
exfoliation. Each trilayer is made by successively stacking an InSb nanosheet
on an hBN flake and on a graphite flake using a home-made alignment
stacking/transfer setup. The fabricated single- and double-gate devices are
characterized by electrical and/or magnetotransport measurements. In all these
devices, the graphite and hBN flakes are employed as the bottom gates and the
gate dielectrics. The measurements of a fabricated single bottom-gate
field-effect device show that the InSb nanosheet in the device has an electron
field-effect mobility of ~7300 cm$^2$V$^{-1}$s$^{-1}$ and a low gate hysteresis
of ~0.05 V at 1.9 K. The measurements of a double-gate Hall-bar device show
that both the top and the bottom gate exhibit strong capacitive couplings to
the InSb nanosheet channel and can thus tune the nanosheet channel conduction
effectively. The electron Hall mobility in the InSb nanosheet of the Hall-bar
device is extracted to be larger than 1.1$\times$10$^4$ cm$^2$V$^{-1}$s$^{-1}$
at a sheet electron density of ~6.1$\times$10$^{11}$ cm$^{-2}$ and 1.9 K and,
thus, the device exhibits well-defined Shubnikov-de Haas oscillations.
