Observation of Meier-Neldel rule in a-Se60Te20Ge20 thin films in presence of light

摘要

In general, in case of semiconductors, conductivity (σ ) varies exponentially with temperature (T), i.e., σ = σ0exp [-. E/k T]. In most of the materials, σ0does not depend on . E. However, in many amorphous and liquid semiconductors and many other class of materials, σ0is found to increase exponentially with . E. This is called Meyer- Neldel rule. This rule is generally verified by selecting different compositions of different . E in a given class of materials. This opens a possibility of change in various other physical properties apart from . E. In the present paper, we report on the observation of Meyer- Neldel rule where . E is varied by varying the intensity of light while measuring the photoconductivity in amorphous thin films of Se60Te20Ge20instead of changing composition of the glassy system. The observation of Meyer-Neldel rule in the present case indicates that this rule is more general and does not fail due to change in density or distribution of defect states or any other physical property due to change in composition