Degradation of current due to charge transport in top gated P3HT-PVA organic field effect transistors

- P3HT-PVA transistors were fabricated by photolithography and plasma etching.
- Source − drain current was directly proportional to channel length.
- Transistors were submitted to drain current stress and degradation was observed.
- Reduction in transistor response was related to reduction in charge carrier mobility.
- The total charge that crossed the transistor was responsible for the degradation.

Top gate-bottom contacts transistors of Poly 3-hexylthiophene (P3HT) and cross-linked Poly Vinyl Alcohol (PVA) with different channel lengths were fabricated by standard photolithography and plasma etching. The transistors presented excellent charge mobility, high ION/IOFF and temporal stability. Drain current was directly proportional to channel length. The transistors were submitted to extended current-voltage measurements and drain current degradation was observed. Reduction in transistor response was found to be related to reduction in charge carrier mobility. Drain Current as a function of the integral charge passing through the channel was investigated. The higher the integrated source − drain current that crossed the transistor, the more prominent was the degradation. The degradation followed the same pattern and persisted indefinitely. The reasons for this behavior are discussed.