Coupled ac photocurrent and photothermal reflectance response theory of semiconducting p-n junctions. I

A formalism involving the ac photocurrent and photothermal reflectance (PTR) spectroscopic response of a semiconducting p-n junction device is presented. The differential equations for the photovoltaic and PTR signals are solved explicitly and special limits of use in experimental applications [J. Appl. Phys. 66, ⧠ ⧠ ⧠ ⧠ (1989), part II] are considered. The dependence of the photocurrent and PTR signal modulation frequency response on electronic transport parameters is identified and the suitability of ac PTR as a noncontact diagnostic technique is assessed in comparison with the more conventional ac photocurrent method.