  A complex interplay between the crystal structure and electron behavior
within borophene renders this material an intriguing 2D system with many of its
electronic properties still undiscovered. Experimental insight into those
properties is additionally hampered by the limited capabilities of the
established synthesis methods, which in turn inhibits the realization of
potential borophene applications. In this multi-method study, photoemission
spectroscopies and scanning probe techniques complemented by theoretical
calculations have been used to investigate the electronic characteristics of a
high-coverage, single-layer borophene on Ir(111) substrate. Our results show
that the binding of borophene to Ir(111) exhibits pronounced one-dimensional
modulation and transforms borophene into a nano-grating. The scattering of
photoelectrons from this structural grating gives rise to the replication of
electronic bands. In addition, the binding modulation is reflected in the
chemical reactivity of borophene and gives rise to its inhomogeneous aging
effect. Such aging is easily reset by dissolving boron atoms in iridium at high
temperature followed by their reassembly into a fresh atomically-thin borophene
mesh. Besides proving electron-grating capabilities of the boron monolayer, our
data provides a comprehensive insight into the electronic properties of
epitaxial borophene which is vital for further examination of other boron
systems of reduced dimensionality.
