  Transition metal chalcogenide tin sulfide (SnS) films as alternative
noncontact alignment layer for liquid crystals, have been demonstrated and
investigated. The SnS has an anisotropic atomic chain structure similar to
black Phosphorous which causes the liquid crystal molecules to align without
the need for any additional surface treatments. The high anisotropic nature of
SnS promotes the alignment of the easy axis of liquid crystal molecules along
the periodic atomic grooves of the SnS layer. The atomically thin SnS layers
were deposited on indium tin oxide films on glass substrates, at room
temperature by chemical vapor deposition. The device characteristics are
comparable to those commercially available, which use photo-aligning polymer
materials. We measured threshold voltage of 0.92V, anchoring energy of
1.573x10^(-6) J/m^2, contrast ratio better than 71:1 and electro-optical
rise/fall times of 80/390ms, respectively for ~11 micron thick liquid crystal
device as expected.

Applied Physics