Surface photovoltage measurement in CdS/CdTe solar cell: Grain boundary effect

The surface photovoltage (SPV) measurements of CdS/CdT solar cells, prepare d by electrodeposition technique, is presented. Minority carrier diffusion length (L) and lifetime (tau) along with the surface space-charge width (W) in the polycrystalline CdTe absorber layers were estimated. A simple modif ication of the existing theory of surface photovoltage (SPV) measurements i s considered to include the effect of grain boundaries in the polycrystalli ne material. It was observed that the value of the diffusion length, derive d from the Goodman's expression, was much higher (almost double) than the v alue obtained by considering the effect of barrier height at the grain boun daries of the polycrystalline absorber layer. This indicated that for SPV m easurements in polycrystalline material the consideration of the effect of grain boundaries becomes essential. The use of Goodman's simplified express ion may not yield unambiguous results, (C) 2000 Elsevier Science B.V. All r ights reserved.