We present a study on the features of the Urbach edge in amorphous silicon dioxide a-SiO2 . The effects of temperature on the absorption edge in the range from 4 to 300 K were studied in both materials having negligible dry, 1017 cm−3 and significant wet, 1019 cm−3 silanol groups contents. Remarkable differences in the values and in the temperature dependence of the Urbach energy in the dry and wet samples were observed. These differences are interpreted as a consequence of a drastic reduction in the degree of disorder in wet materials, which turn out to be characterized by an electronic structure more similar to that of crystalline quartz. Furthermore, our results indicate that silanol groups affect the thermal component of disorder, modifying the vibrational modes of the network.

Vella, E., & Boscaino, R. (2009). Sturctural disorder and silanol groups content in amorphous SiO2. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 79(8), 085204-1-085204-7 [10.1103/PhysRevB.79.085204].

Sturctural disorder and silanol groups content in amorphous SiO2

VELLA, Eleonora;BOSCAINO, Roberto
2009

Abstract

We present a study on the features of the Urbach edge in amorphous silicon dioxide a-SiO2 . The effects of temperature on the absorption edge in the range from 4 to 300 K were studied in both materials having negligible dry, 1017 cm−3 and significant wet, 1019 cm−3 silanol groups contents. Remarkable differences in the values and in the temperature dependence of the Urbach energy in the dry and wet samples were observed. These differences are interpreted as a consequence of a drastic reduction in the degree of disorder in wet materials, which turn out to be characterized by an electronic structure more similar to that of crystalline quartz. Furthermore, our results indicate that silanol groups affect the thermal component of disorder, modifying the vibrational modes of the network.
Settore FIS/01 - Fisica Sperimentale
Vella, E., & Boscaino, R. (2009). Sturctural disorder and silanol groups content in amorphous SiO2. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 79(8), 085204-1-085204-7 [10.1103/PhysRevB.79.085204].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/38694
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