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The Origin of the High Off-State Current in p-Type Cu₂O Thin Film Transistors

Accepted version
Peer-reviewed

Type

Article

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Authors

Flewitt, AJ 

Abstract

There is a need for a good quality p-type accumulation-mode thin film transistor (TFT) using a metal oxide semiconducting channel. P-type cuprous oxide (Cu₂O) has been proposed as a suitable semiconductor, but such TFTs have suffered from unacceptably high off-state currents. This paper studies the main origin of this high off-state current. Capacitance-voltage (C-V) characteristics reveal the accumulation of minority carriers (electrons) in the off-state regime (i.e. for a positive gate voltage). The activation energy extracted from the temperature dependence of the drain current as a function of gate voltage shows an abrupt lowering of the activation energy and pinning of the Fermi energy in the off-state region, which is attributed to subgap states at 0.38 eV from the conduction band minimum. This suggests that an electron flow in the off-state causes the high off-state current in p-type Cu₂O TFTs and not an inability to deplete the channel of holes.

Description

Keywords

cuprous oxide (Cu2O), off-state current, p-type metal oxide, sputtering, thin film trators (TFTsnsis)

Journal Title

IEEE Electron Device Letters

Conference Name

Journal ISSN

0741-3106
1558-0563

Volume Title

38

Publisher

IEEE
Sponsorship
Engineering and Physical Sciences Research Council (EP/M013650/1)
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