  The availability of large-area substrates imposes an important constraint on
the technological and commercial realization of devices made of layered
materials. Aluminum nitride films on silicon are shown to be promising
candidate materials as large-area substrates for such devices. Herein, the
optical contrast of exemplar 2D layers - MoS2and graphene - on AlN films has
been investigated as a necessary first step to realize devices on these
substrates. Significant contrast enhancements are predicted and observed on AlN
films compared to conventional SiO2films. Quantitative estimates of
experimental contrast using reflectance spectroscopy show very good agreement
with predicted values.
