Electronic-beam evaporation processed titanium oxide as an electron selective contact for silicon solar cells

This work is dedicated to the study of electronic-beam (e-beam) evaporated titanium oxide (TiO_x) contact for polycrystalline silicon hetero-junction solar cells. A TiO_x material obtained by e-beam evaporation method is suggested as a possible alternative to the atomic layer deposition (ALD) process. The purpose is to achieve corresponding passivation efficiency between e-beam evaporation of TiOx and the ALD method. However, the TiOx in question achieved a relatively low passivation performance of S_eff = 113 cm⁻¹ in comparison to the reported ALD results. Nonetheless, as e-beam evaporation is well-established and an environmentally friendly deposition technology, e-beam evaporated TiO_x passivation layer has potential for improvement. What is clearly demonstrated in our work is how such an improvement in contact resistance dropped from >55 Ω/cm² to 2.29 Ω/cm². Indeed, our study established a correlation between the main process parameters of e-beam evaporation and their influence on the quality of electron selective TiO_x layer. Moreover, we reveal a possible scenario for the implementation of e-beam evaporated Titanium oxide as electron selective contact for asymmetrical hetero-junction solar cells.