  The performance of an organic-semiconductor device is critically determined
by the geometric alignment, orientation, and ordering of the organic molecules.
While an organic multilayer eventually adopts the crystal structure of the
organic material, the alignment and configuration at the interface with the
substrate/electrode material is essential for charge injection into the organic
layer. This work focuses on the prototypical organic semiconductor
para-sexiphenyl (6P) adsorbed on In$_2$O$_3$(111), the thermodynamically most
stable surface of the material that the most common transparent conducting
oxide, indium tin oxide (ITO) is based on. The onset of nucleation and
formation of the first monolayer are followed with atomically-resolved scanning
tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM).
Annealing to 200$^\circ$C provides sufficient thermal energy for the molecules
to orient themselves along the high-symmetry directions of the surface, leading
to a single adsorption site. The AFM data suggests a twisted adsorption
geometry. With increasing coverage, the 6P molecules first form a loose network
with poor long-range order. Eventually the molecules re-orient and form an
ordered monolayer. This first monolayer has a densely packed, well-ordered
(2$\times$1) structure with one 6P per In$_2$O$_3$(111) substrate unit cell,
i.e., a molecular density of 5.64$\times$10$^{13}$ cm$^{-2}$.
