Theory of the photovoltage at semiconductor surfaces and its application to diffusion length measurements

Surface photovoltage phenomena: theory, experiment, and applications

“…Similar results have also been obtained by Jang using a somewhat different approach [87]. Finally, Choo has studied numerically both the free surface SPV [77] and the metal±semiconductor interface SPV [80], and concluded that typically the FQL approximation is considerably more satisfactory in the former than in the latter.…”

“…Chiang and Wagner [73] assumed a similar equality, SPV F n À F p À Á xw . Unfortunately, the latter relation is erroneous for the case of a free surface [77]. As opposed to the case depicted in Fig.…”

“…Choo et al [77] presented a current balance calculation which is simpler than Chiang and Wagner's. By integrating the steady-state continuity equation across the SCR, the relation:…”

“…Thus, under the FQL approximation, the SPV may be found by numerically solving algebraic equations, but not differential ones. Moreover, in some cases analytical expressions can be obtained [77,78].…”

“…Here, the parabolic potential naturally limits the validity of the treatment to the depletion regime. Worse, under certain conditions a semiconductor in the depletion regime may invert upon illumination [77]. However, when applied with care the approximation may yield very good results.…”