Resolving ambiguities in nanowire field-effect transistor characterization.

Area of Science:

• Semiconductor Physics
• Materials Science
• Nanotechnology

Background:

• Indium arsenide (InAs) nanowires are crucial for advanced electronic devices.
• Accurate characterization of carrier transport in nanowires is challenging.
• Surface states significantly influence the electrical properties of nanowires.

Purpose of the Study:

• To develop a comprehensive model for InAs nanowires accounting for device geometry and surface states.
• To investigate the impact of surface states on charge distribution and gate control.
• To provide an accurate method for determining electron concentration and mobility in nanowires.

Main Methods:

• Finite element method (FEM) modeling of InAs nanowire devices.
• Incorporation of actual device geometry, semiconducting channel properties, and surface/interface states.
• Analysis of field-effect transistor (FET) measurements with dual gates of varying couplings.

Main Results:

• Gate coupling is significantly affected by concurrent coupling to surface/interface states.
• Identified the surface state density responsible for a shallow quantum well at the nanowire surface.
• Achieved consistent electron concentration and mobility values using the actual surface state density.

Conclusions:

• The developed model accurately captures carrier behavior in InAs nanowires.
• The study highlights the critical role of surface states in undoped nanowires.
• This approach provides a reliable and simplified alternative to conventional Hall effect measurements for nanowire characterization.