Effect of Threshold Voltage on Field-Effect Transistor and Phototransistor Performance Based on Pentacene

Authors

  • Bushra Hussein University of Thi -Qar / College of Science
  • Noora H. Ali Department of Physics, College of Science, University of Thi-Qar

DOI:

https://doi.org/10.32792/utq/utjsci/v13i1.1495

Keywords:

OFET, Threshold voltage Vth, phototransistor

Abstract

This study shows that the suggested model greatly improves the OFET-based photodetector's performance for the organic semiconductor pentacene and the dielectric polyvinyl alcohol (PVA).  This model shows how the threshold voltage affects both types' electrical characteristics (the output and transfer).  Various incident optical power (Popt) values between 100 and 1000 μW/cm² were tested.  The results show that the threshold voltage exhibits nonlinear behaviour, rising as incident optical power increases. Where MATLAB software simulation is used to calculate the electrical properties output (Id-Vd) and transfer (Id-Vg) properties, including current (Id) values, switching ratio (Ion/Ioff), and responsivity (R).   Pentacene exhibits transfer and output properties typical of p-type OFETs.  The ideal drain current value for output (Id-Vd) and transfer (Id-Vg) properties is found at an incident optical power of Popt = 1000 W/cm2, a threshold voltage of Vth = -0.63 V, and a gate voltage of Vg = -30 V.  While the responsivity shows the opposite behavior, the observed switching ratio values increase as the threshold voltage and incident optical power decrease. The OFET-based photodetector functioned best at the lowest threshold voltage value of -0.63 V.  This decrease in threshold voltage (Vth) is critical for OFET-based electronic applications because it boosts photocurrent and enhances responsiveness R.

Received: 2025-10-02

Revised: 2025-11-28

Accepted: 2025-12-13

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Published

2026-06-01

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Vol. 13 No. 1 (2026)

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How to Cite

Hussein, B., & Ali, N. (2026). Effect of Threshold Voltage on Field-Effect Transistor and Phototransistor Performance Based on Pentacene. University of Thi-Qar Journal of Science, 13(1), 62-67. https://doi.org/10.32792/utq/utjsci/v13i1.1495