Kühnapfel, S.; Huang, J.; Teal, A.; Kampwerth, H.; Amkreutz, D.; Gall, S.; Varlamov, S.: Lifetime analysis of laser crystallized silicon films on glass. Journal of Applied Physics 118 (2015), p. 055304/1-5
10.1063/1.4928156
Abstract:
Only recently the quality of liquid phase crystallized silicon directly on glass substrates made a huge leap towards the quality of multi-crystalline wafers with open circuit voltages well above 600 mV. In this paper we investigate the material quality in order to identify the factors limiting further performance improvements. We employ photoluminescence imaging on a state of the art test structure with lifetime calibration by transient photoluminescence. The resulting lifetime map is converted into an effective diffusion length map and the origin of regions with short lifetimes is investigated with electron backscattering and transmission electron microscopy. High local dislocation densities in areas with dissociated coincidence site lattice boundaries were found to be responsible for the localised quenching of the photoluminescence signal.