We have analyzed the photoresponse of solar blind Schottky barrier photodiodes below the alloy band gap energy, in the range, and we show that it is dominated by internal photoemission. The -type Schottky barrier height is shown to increase linearly with the band gap energy of the alloy. The amplitude of the internal photoemission signal is about 20 times smaller than the value given by the Fowler theory based on a free electron model. We explain this result by taking into account the interband transitions and the ballistic transport of photoexcited electrons in the metal. This low value of internal photoemission allows us to achieve a spectral rejection ratio between 280 and of more than 3 decades.
Internal photoemission in solar blind Schottky barrier photodiodes
Jean-Yves Duboz, Nicolas Grandjean, Franck Omnes, Mauro Mosca, Jean-Luc Reverchon; Internal photoemission in solar blind Schottky barrier photodiodes. Appl. Phys. Lett. 7 February 2005; 86 (6): 063511. https://doi.org/10.1063/1.1862780
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