The dark forward and reverse current-voltage characteristics of a typical BPW34 silicon photodiode have been investigated in the temperature range 80-300 K. We propose that tunnelling enhanced recombination at or close to the p/i interface plays a significant role in the dark forward current. We show that Bardeen's model for a modified Schottky-like interfacial junction can be satisfactorily applied to describe the reverse current-voltage characteristics at intermediate bias voltages. (c) 2006 Elsevier Ltd. All rights reserved.