Comparison between MPD and SPV techniques

MDP (microwave detected photoconductivity): sensitive to moving photogenerated charge carriers (bulk property)

SPV (surface photovoltage): sensitive to surface AND bulk properties with respect to ANY photogenerated charge carriers separated in space (moving or trapped)

The MDP method does only apply to moderately doped semiconductors or close to perfect optical crystals

The SPV method apply to any photoactive materials allowing for charge separation in space (semiconductors, multilayer and multijunction structures, molecular layers, powders)

The MDP method can be modelled as a time dependent resistance measurement (DC), t_MDP

The SPV method can be modelled as a frequency and time dependent capacitance measurement (DC/modulation), t_SPV 

For a non-ideal semiconductor (with defects), there can be a huge difference between the two methods, both methods provide complementary information about bulk and surface properties