Estimating pyramid density of a random-textured surface by capacitance-voltage measurement of c-Si solar cells

Random surface texturing allows efficient light-trapping and therefore, is widely used in commercial c-Si PV technology. The geometry, periodicity, and interface characteristics of the texture greatly impact the efficiency of the c-Si solar cells, and thus, the ability to evaluate the texture `quality´ in a time-and-cost effective manner without sophisticated metrology is desired. In this paper, we report a simple and efficient algorithm to estimate the pyramid density via standard capacitance-voltage measurement. We demonstrate that the overall capacitance of a random pyramid surface can be decomposed into three distinct capacitive components, and this decomposition can be used to estimate the pyramid density. We validate the algorithm by sampling the pyramid density of commercial c-Si solar cells and show that the density obtained from image analysis is consistent with the estimates suggested by the purposed model.