Threshold Voltage Drift in H+-sensitive FETs and Drift of Luminance in Organic Light-emitting Diodes: The role of Dispersive Diffusion

Document Type : Original Article

Authors

1 Department of Basic Science, Hamedan University of Technology, Hamedan, Iran

2 Biomedical Engineering Department,, Hamedan University of Technology

Abstract

The drift phenomenon is manifested as instability in the operating point of the H+-sensitive (pH-sensitive) ion-selective field effect transistor as well as that of the organic light-emitting diode. Specifically, in the pH-sensitive ion-selective field effect transistor, drift is observed as a slow temporal and unidirectional change in the threshold voltage, and hence, the dc bias current of the device. In the organic light-emitting diode, on the other hand, drift is detected as a decrease in luminance with time. The operating point drift in both devices has been modeled based on a diffusion mechanism, known as dispersive diffusion, which involves hopping between trap energy states. Notably, the similarity between the time dependence of drift in these devices is due to the characteristic temporal behavior of the dispersive diffusion coefficient, which obeys a power law characterized by a time dependence of the form 〖(t)〗^(β-1), where β is the dispersion parameter, which satisfies 0<β<1.

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History

  • Receive Date: 12 November 2021
  • Revise Date: 19 March 2022
  • Accept Date: 14 January 2023
  • First Publish Date: 14 January 2023

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