The spectral photoconductivity is a powerful tool for measuring the bandgap energy and photoelectronic inter-band transitions in semiconductors, with the possibility of determining the joint density of defect states within the bandgap. The technique allows evaluating the responsivity and the quantum efficiency of a material as a function of photon energy, defined as the capability to convert absorbed photons into charge carriers.
It is based on the measurement of the photocurrent, collected by applying an electric field on the device under test and induced by the interaction with a modulated and monochromatic radiation. The electronic chain for this kind of measurements is particularly sensitive and is made up by a mechanical chopper, a trans-impedance amplifier, a lock-in amplifier, and a voltage source.
English (UK) 
Italiano (Italia)