Frequency dependent series resistance and interface states in Au/bio-organic/n-GaN Schottky structures based on DNA biopolymer

•A detailed investigation of C–V–f and G/ω–V–f characteristics of Au/DNA/n-GaN SBDs studied.•The interface states in Au/DNA/n-GaN SBDs are determined.•The effect of series resistance to obtain the real diode capacitance and conductance.•C–V–f and G/ω–V–f characteristics strongly affect the electrical properties.

The frequency dependent capacitance-voltage (C–V) and conductance-voltage (G/ω–V) characteristics of Au/bio-organic/n-GaN Schottky barrier diodes (SBDs) based on DNA biopolymer is investigated in the frequency range of 200 KHz–2 MHz at room temperature. The electrical characteristics of SBDs with DNA biopolymer is analyzed based on voltage and frequency dependent series resistance and frequency dependent interface states (NSS). The values of measured capacitance Cm and conductance Gm under both reverse and forward bias have been corrected for the effect of series resistance (RS) to obtain the real diode capacitance and the conductance values. The extracted corrected capacitance and conductance are found to be strongly dependent on bias voltage and frequencies for the Au/DNA/n-GaN SBDs. The RS–V plots exhibit a peak decrease the increasing frequencies. It is also noted that the interface states decreases exponentially with increasing frequency. The C–V–f and G/ω–V–f characteristics confirm that the series RS and NSS of the Au/DNA/n-GaN are significant parameters that strongly affect the electrical parameters in metal/bio-organic/inorganic semiconductor structures.

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