  Monolayer of hexagonal boron nitride (h-BN), commonly known as "white
graphene" is a promising wide bandgap semiconducting material for
deep-ultaviolet optoelectronic devices. In this report, the light absorption of
a single layer hexagonal boron nitride is calculated using a tight-binding
Hamiltonian. The absorption is found to be monotonically decreasing function of
photon energy compared to graphene where absorption coefficient is independent
of photon energy and characterized by the effective fine-structure constant.
