  Silicon photonics has many attractive features but faces a major issue:
inefficient and slow photodetection in the telecom range. New
metal-semiconductor Schottky photodetectors based on intraband absorption
address this problem, but their efficiency remains low. We suggest that by
creating a junction between silicon and a transparent oxide with appropriate
doping, which results in a real permittivity close to zero (known as the
epsilon near zero or ENZ regime), detection efficiency could increase by more
than tenfold. Using Aluminum Zinc Oxide (AZO) as an example, we design an
optimized AZO/Si slot photonic waveguide detector that could potentially reach
an efficiency of several tens of percent, in contrast to a few percent for a
metal/Si Schottky detector. This increase is primarily due to the lower density
of states in AZO compared to metal, along with superior coupling efficiency and
strong absorption within a 10 nm slot.
