First Solar Cells on Exfoliated Silicon Foils Obtained at Room Temperature by the SLIM-Cut Technique Using an Epoxy Layer

In this paper, we report on the first solar cells fabricated on silicon foils employing the stress-induced liftoff method-cut technique and using an epoxy stress-inducing layer. The latter is a 900-mu m-thick epoxy layer, which was manually dispensed on the surface of a monocrystalline silicon sample and cured at 150 degrees C for 1 h. The crack propagation is then activated by cooling down the sample to room temperature on an aluminum plate. The structural and electrical properties of the resulting silicon foils are presented. The thickness of the silicon foil and the maximum roughness height after this process are found to be around 130 and 37.4 mu m, respectively. Tensile and compressive regions present in the foil were detected by the birefringence technique and indicate the formation of structural defects such as dislocations during the process. Average minority carrier lifetimes around 28 mu s were measured on n-type silicon foils after surface passivation by an iodine-ethanol solution. Photon conversion efficiencies of 12.6% and 13.4% are measured using conventional sun simulator (1-sun AM1.5G) and SINTON Suns-Voc setup systems, respectively.