D. Caputo et al., A SYSTEMATIC INVESTIGATION OF THE ROLE OF MATERIAL PARAMETERS IN METASTABILITY OF HYDROGENATED AMORPHOUS-SILICON, Journal of non-crystalline solids, 170(3), 1994, pp. 278-286
In this work, the role of structural, electronic and optical parameter
s of as-deposited amorphous silicon films in photoconductivity decay d
uring light soaking was systematically investigated. Deposition temper
ature was varied in the range 130-270-degrees-C, in order to obtain sa
mples with different structural, optical and electronic properties. As
a result, two degradation regimes were identified. At short illuminat
ion times (within a few days in typical samples, and within a few hour
s in the low quality samples), the material showed different tendency
to degradation depending on the content of the SiH bond clusters. At l
ong illumination times, in all the light soaked samples the photocondu
ctivity decay followed the t-1/3 law. The measured photoconductivity d
egradation was simulated starting from the bond-breaking model. The ob
served correlation between the material structural parameters and the
different tendencies to degradation is explained in terms of variation
s of the Staebler-Wronski susceptibility.