A model calculation for surface plasma-enhanced internal photoemission in Schottky-barrier photodiodes

Attenuated total reflection is commonly used to excite the surface plasma wave (SPW) on a metal film. The SPW traveling on the surface of the metal will enhance the emission of photoelectrons from the metal into the semiconducting region of a Schottky barrier photodiode. A model consisting of an aluminum film on n-type gallium arsenide forming a Schottky barrier photodiode is used to predict the enhanced emission of photoelectrons over the barrier between the aluminum film and the gallium arsenide. The quantum efficiency for this model shows a strong dependence on parameters such as the electron escape depth, film thickness, and the spacer thickness between the prism coupler and the photodiode. The model proved to be effective when used to fit quantum efficiency and reflectivity data resulting from an angle scan experiment.