The Role of Surface Roughness in Plasmonic-Assisted Internal Photoemission Schottky Photodetectors

Internal photoemission of charged carriers from metal to semiconductors plays an important role in diverse fields such as sub-bandgap photodetectors and catalysis. Typically, the quantum efficiency of this process is relatively low, posing a stringent limitation on its applicability. Here, we show that the efficiency of hot carrier injection from a metal into a semiconductor across a Schottky barrier can be enhanced by as much as an order of magnitude in the presence of surface roughness on the scale of a few atomic layers. Our results are obtained using a simple semianalytical theory and indicate that properly engineered plasmonic-assisted internal photoemission photodetectors can be a viable alternative in silicon photonics. Other applications, such as plasmonic-enhanced photocatalysis, can also benefit from these results.