Summary
We have found, from optical transmission and photoconductivity measurements, that the width of the Urbach’s tail and the optical-band gap value depend on the amount of disorder present in the network of a-Si: H films. The nature of the disorder, being it thermal or structural, affects in the same way the behaviour of the absorption coefficient and supports the hypothesis that the value of the optical-band gap depends only indirectly on the overall hydrogen content.
Riassunto
Mediante misure di assorbimento ottico e di fotoconducibilità si è trovato che la larghezza della coda di Urbach e il valore del gap ottico dipendono fortemente dal disordine presente nella matrice dei film di silicio amorfo idrogenato. Inoltre si è osservato che il disordine termico e quello strutturale influenzano allo stesso modo il coefficiente di assorbimento avvalorando l’ipotesi che il valore del gap ottico dipende solo indirettamente dalla concentrazione totale di idrogeno.
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Work partially supported by CNR «Progetto Finalizzato Energetica» and by the Energy Committee of Sicilian Region.
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Grasso, V., Mezzasalma, A.M., Mondio, G. et al. Disorder and optical characterization of evaporation deposited a-Si: H films. Nouv Cim D 1, 841–848 (1982). https://doi.org/10.1007/BF02451073
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DOI: https://doi.org/10.1007/BF02451073