Dimensional Scaling Effect in Percolative Oxide Semiconductor Transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Electrical Engineering

Background:

• Percolation theory describes charge transport in amorphous and polycrystalline semiconductors.
• Transistor performance is typically understood through electrostatics and quantum confinement.

Purpose of the Study:

• To identify and characterize a dimensional scaling effect in transistors utilizing percolative semiconductors.
• To establish a quantitative link between the percolation threshold (p_c) and transistor threshold voltage (V_T).

Main Methods:

• Investigating the correlation between semiconductor channel geometry and device electrical characteristics.
• Utilizing scanning tunneling microscopy to visualize the percolation potential landscape.
• Performing temperature-dependent transport measurements.

Main Results:

• A strong correlation was found between the percolation threshold (p_c) and transistor threshold voltage (V_T).
• Device geometry (thickness, width, length) fundamentally governs both p_c and V_T by constraining conductive pathways.
• The Fermi level and potential barriers dictate device turn-on in percolative channels, confirmed by microscopy and transport measurements.
• This geometric scaling effect is universal across n-type In2O3 and p-type SnO transistors.

Conclusions:

• Transistor behavior in amorphous semiconductors is dominated by percolation transport, not conventional electrostatics.
• Semiconductor channel geometry is a critical design parameter for amorphous electronic devices.
• This study redefines the understanding of charge transport mechanisms in amorphous semiconductor devices.