Field-induced anomalous changes in Cr/a-Si:H/V thin film structures

Experimental results on the electronic properties of conditioned Cr/hydrogenated amorphous silicon (a-Si:H)/V thin film devices are presented. The devices under test were electro-formed, and had resistances in the range from several hundred Ohms to several kiloOhms. The current of conditioned device...

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Bibliographic Details
Published inThin solid films Vol. 396; no. 1; pp. 242 - 251
Main Authors Hu, J., Snell, A.J., Hajto, J., Rose, M.J., Edmiston, W.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 21.09.2001
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Summary:Experimental results on the electronic properties of conditioned Cr/hydrogenated amorphous silicon (a-Si:H)/V thin film devices are presented. The devices under test were electro-formed, and had resistances in the range from several hundred Ohms to several kiloOhms. The current of conditioned devices varied non-linearly with bias at low voltages, but exhibited ‘jumps’ at a threshold voltage ( V th) (typically 2–3 V), leading to a resistance change of one to three orders of magnitude. Above V th the current increased almost linearly with bias, and the carrier transport changed from a semiconducting behaviour to a more conducting (metallic) state. This was confirmed by a.c. characteristics of the conditioned devices, which showed a transition from a capacitive to an inductive behaviour around V th. The threshold voltage V th, was found to decrease with increasing temperature and disappeared at 340–350 K, but recovered when the temperature was reduced. The transition at V th has been analysed in terms of an electrothermal mechanism. The calculated turnover temperature is approximately 346 K, close to that for the disappearance of V th. We suggest that the observed transition could involve vanadium oxides such as VO 2. The phase transition could also facilitate the underlying ‘quantisation’ effect.
ISSN:0040-6090
1879-2731
DOI:10.1016/S0040-6090(01)01188-9