Deconvolution of Charge Injection Steps in Quantum Yield Multiplication on Silicon

An unusual photocurrent multiplication effect at the n-silicon/electrolyte interface which gives rise to quantum efficiencies approaching 400% has been investigated by intensity-modulated photocurrent spectroscopy. This technique has shown that the process involves hole capture followed by the successive injection of three electrons by surface intermediates. Kinetic analysis of this effect shows that the rate constants for electron injection are unusually low at between 1 and 10³ s^-1.