Very low bias stress in n-type organic single crystal transistors

TL;DR

This study demonstrates that n-type organic single-crystal transistors exhibit extremely low bias stress effects, maintaining high stability over extended periods and outperforming p-channel counterparts in terms of bias stress resilience.

Contribution

The paper reports the first observation of very low bias stress in n-type organic single-crystal transistors, with exceptionally long characteristic time constants indicating superior stability.

Findings

Bias stress causes only ~1% current decrease in vacuum.

Bias stress causes only ~10% current decrease in air.

Characteristic time constants are around 2-5 billion seconds, much longer than previous p-channel OFETs.

Abstract

Bias stress effects in n-channel organic field-effect transistors (OFETs) are investigated using PDIF-CN2 single-crystal devices with Cytop gate dielectric, both under vacuum and in ambient. We find that the amount of bias stress is very small as compared to all (p-channel) OFETs reported in the literature. Stressing the PDIF-CN2 devices by applying 80 V to the gate for up to a week results in a decrease of the source drain current of only ~1% under vacuum and ~10% in air. This remarkable stability of the devices leads to characteristic time constants, extracted by fitting the data with a stretched exponential - that are \tau ~ 2\cdot10^9 s in air and \tau ~ 5\cdot10^9 s in vacuum - approximately two orders of magnitude larger than the best values reported previously for p-channel OFETs.