Method of neutralization in ITO/poly-Si junctions

The presence of interfacial states at the grain boundaries (GB) and within the grains in polycrystalline silicon (poly-Si) leads to a substantial loss in poly-Si solar cell performance. Hence, the neutralization of these traps is on critical importance. Neutralization was performed by implanting iodine ions prior to sputtering of a transparent conductor (indium tin oxide) for both poly-Si and single crystal silicon (SC-Si). A model for a typical Schottky type polycrystalline junction is described and an equivalent circuit for the space charges is given. The results of I-V characteristic demonstrated that neutralization took place both at the junction and at the GB. C-V measurements and deep level transient spectroscopy (DLTS) both confirmed the role of iodine as a neutralizing agent