Title: Electrical characterization of structured platinum diselenide devices,
Abstract: Platinum diselenide (PtSe2) is an exciting new member of the two-dimensional
(2D) transition metal dichalcogenide (TMD) family. it has a semimetal to
semiconductor transition when approaching monolayer thickness and has already
shown significant potential for use in device applications. Notably, PtSe2 can
be grown at low temperature making it potentially suitable for industrial
usage. Here, we address thickness dependent transport properties and
investigate electrical contacts to PtSe2, a crucial and universal element of
TMD-based electronic devices. PtSe2 films have been synthesized at various
thicknesses and structured to allow contact engineering and the accurate
extraction of electrical properties. Contact resistivity and sheet resistance
extracted from transmission line method (TLM) measurements are compared for
different contact metals and different PtSe2 film thicknesses. Furthermore, the
transition from semimetal to semiconductor in PtSe2 has been indirectly
verified by electrical characterization of field-effect devices. Finally, the
influence of edge contacts at the metal - PtSe2 interface has been studied by
nanostructuring the contact area using electron beam lithography. By increasing
the edge contact length, the contact resistivity was improved by up to 70%
compared to devices with conventional top contacts. The results presented here
represent crucial steps towards realizing high-performance nanoelectronic
devices based on group-10 TMDs.