Quantum detectors using cycling excitation process in disordered medium

Cycling excitation process (CEP) is a signal amplification mechanism showing high gain, low noise at low operation bias1,2. Depending on Auger excitation that involves localized states, CEP effect may be prominent in amorphous silicon, which has abundant localized states as a disordered material. Here we present a carbon-doped amorphous Si photodiode with ultra-high gain-bandwidth product with exceedingly low excess noise factor.