Analytic Device Model of Organic Field-Effect Transistors with Doped Channels.

Area of Science:

• Organic electronics
• Semiconductor device physics

Background:

• Doping is crucial for tuning organic field-effect transistor (OFET) performance and stability.
• Existing models often simplify doping profiles, potentially limiting design accuracy.

Purpose of the Study:

• To present an analytical model for doping effects on OFET transfer characteristics.
• To validate the model experimentally and investigate real doping profiles.

Main Methods:

• Developed an analytical model assuming a square doping profile.
• Experimentally fabricated and tested OFETs with varied doping.
• Used AC small-signal drift-diffusion simulations to determine precise doping profiles via capacitance/voltage measurements of metal-insulator-semiconductor (MIS) junctions.

Main Results:

• The analytical model accurately describes OFET behavior despite deviations from ideal square doping profiles.
• Real doping profiles show reduced effective concentration at the dielectric/semiconductor interface.
• Model sensitivity analysis confirmed that total charge density, not profile shape, dictates transistor behavior changes.

Conclusions:

• The analytical model provides reliable predictions for doped OFETs.
• Deviations in doping profiles do not invalidate the model's core predictions.
• The study offers new design guidelines for optimizing doped OFET performance.