8/14/2019 DC electric-field effect in bulk and thin-film Ge 5 As 38 Te 57 chalcogenide glass

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Vacuum 59 (2000) 845}853

DC electric-"eld e!ect in bulk and thin-"lm Ge

As

Te

chalcogenide glass

A. Abdel-All*, A. Elsha"e, M.M. Elhawary

Physics Department, Faculty of Science, Helwan University, Cairo, Egypt

Physics Department, Faculty of Science, El-Menouxa University, Shebin El-Koom, Egypt

Abstract

The electrical properties of Ge

As

Te

have been carried out as a function of temperature at di!erent dc

electric "elds for the bulk and thin "lms. This material shows a non-ohmic behaviour by switching to

a negative resistance state. The activation energy was found to decrease slowly as the electric "eld increases

and increases again before switching to the negative region. The conduction is simply a "eld-dependent

hopping mobility at low "elds. The high-"eld conduction mechanisms have been explained in terms of thePoole}Frenkel e!ect and Schottky emission of carriers which is applicable to both bulk and thin

"lms. 2000 Elsevier Science Ltd. All rights reserved.

Keywords: Chalcogenide; Switching; Electric "eld

1. Introduction

Many studies have been made on the switching phenomena in chalcogenide glasses and thecause of the switching phenomena has been classi"ed into those initiated thermally [1,2] and thoseinitiated electronically [3,4]. Ovshinsky [5] discussed the major features of switching phenomena

in TeAsSiGe . Mehra et al. [6] reported the thermally initiated switching characteristic inbulk Se-Te-Ge systems. They found that