Gate-tunable graphene-based Hall sensors on flexible substrates with increased sensitivity

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene-based Hall sensors offer potential for sensitive magnetic field detection.
• Static operation of Hall sensors is limited by noise and sensitivity issues.
• Existing flexible Hall sensors often lag behind rigid counterparts in performance.

Purpose of the Study:

• To demonstrate a novel operating concept for graphene-based Hall sensors using AC modulated gate voltage.
• To enhance sensor sensitivity by utilizing both n- and p-type conductance.
• To reduce 1/f noise and offset voltage for improved signal-to-noise ratio.

Main Methods:

• Utilizing an alternating current (AC) modulated gate voltage for graphene Hall sensor operation.
• Employing both n- and p-type conductance for enhanced sensitivity.
• Operating sensors at kHz frequencies to leverage lower 1/f noise.

Main Results:

• Achieved doubled sensor sensitivity by exploiting both n- and p-type conductance.
• Enabled static magnetic field readout in the kHz range with reduced 1/f noise.
• Significantly reduced offset voltage, increasing the signal-to-noise ratio.
• Demonstrated a minimal detectable magnetic field (Bmin) down to [Formula: see text] and sensitivity up to 0.55 V/VT on flexible polyimide substrates.

Conclusions:

• The AC modulated gate voltage concept significantly enhances graphene Hall sensor performance.
• This novel approach outperforms state-of-the-art flexible Hall sensors and rivals rigid semiconductor sensors.
• The developed technology holds promise for advanced magnetic sensing applications, particularly on flexible platforms.