Scanning probe study on the photovoltaic characteristics of a Si solar cell by using Kelvin force microscopy and photoconductive atomic force microscopy

Poly-Si-based solar cells, prepared via conventional Si processes including phosphoryl chloride(POCl3) doping and diffusion, were investigated in this study in terms of their electrical and optical properties, including open-circuit voltage (Voc), short-circuit current (Isc), fill factor, external quantum efficiency and efficiency, employing a few recognized test methods. Also, we compared the experiment results from an identical specimen via Kelvin force microscopy (KFM) and photoconductive atomic force microscopy (PC-AFM), respectively, verifying that the scanning probe technique is very effective both in photovoltaic effect measurement and mechanism establishment. When the results of both conventional and nano-probing techniques are compared, the behavior of the surface potential property is similar to the Voc, and that of the photoinduced current property is similar to the Isc. Through this study, we have demonstrated that the KFM and the PC-AFM are effective tools to monitor and evaluate the properties of solar energy-producing materials and devices.