Optical absorption below and near the interband absorption edge has been measured from helium temperatures up t o the molten state of As& Irreversible changes in absorption below the band edge suggest that heating above 530 K produces defect states in crystalline As$,. The exponential absorption tail and thus the absorption edge is temperature independent t o about 200K. Between 300 and 400K it decreases a t a rate of about 1.6 X lo-, eV/K. This temperature dependence is predominantly caused b y electron-phonon interaction.Die optische Absorptionskonstante von A@, wurde im Bereich der Bandkante zwischen Heliumtemperaturen und dem Schmelzzustand gemessen. Irreversible Anderungen in der Absorption unterhalb der Bandkante legen nahe, da13 sich oberhalb 530 K Defektstellen in As$,-Kristallen bilden. Die der Bandkante vorgelagerte exponentiell ansteigende Absorptionskurve und somit die Lage der Bandkante ist teinperaturunabhsngig his hinauf zu 200 K. Zwischen 300 und 400 K verschiebt sich die Absorptionskante zu kleineren Photonenenergien mit einem Temperaturkoeffizienten von etwa 1,6 x lo-, eV/K. Diese Temperaturabhangigkeit ist weitgehend durch die Elektronen-Phononen-Wechselwirkung bedingt.
Subject classification: 1 0 . 2 ; 20.1; 2 2 . 5 . 2 Latvian State University, Riga Anion Vacancy Trapping in KC1 BY J.R. ZAKIS and V.P. ZEIKATS Anion vacancy migration and trapping in alkali halides a r e investigated by using molecular impurity anions a s detectors. The method is based on the sensitivity of the internal vibration modes of the molecular impurities to the presence of other defects in the nearest neighbour position (1). KC1 crystals with sulfate anions a r e
Optical absorption and electron spin resonance (ESR) attributed to X‐ray induced localized paramagnetic states are studied in glassy As2Se3 and As2Se3 for T ≧ 77 K. The production of induced paramagnetic states is not detected in crystalline As2S3. X‐ray irradiation of a crystal at 77 K excites luminescence with the same spectrum as that for photoluminescence. No X‐ray excited luminescence is observed in glasses at 77 K. It is shown that a unified explanation for the data can be given on the basis of the Mott‐Davis‐Street model.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.