A natural dye-based Schottky diode with observed quantum tunnelling and determined trap density, mobility, and excellent sensitivity and nonlinearity

Trap density (N_t), density of carriers (n_o) and mobility are extracted in Al/beetroot/Cu Schottky diode using the Poisson’s equation. The trap density and carrier concentration were found to be 1.25 × 10⁹ and 1.8 × 10⁹ cm^–3, respectively, with the mobility 124.54 cm² v⁻¹ s⁻¹ for Al/beetroot/Cu. The device shows highly asymmetric current–voltage characteristics with a good degree of nonlinearity. The diode shows an acceptable low-voltage large signal and small signal nonlinearities with asymmetry of 17.6 at 0.85 V, maximum rate of change of nonlinearity of 6 and sensitivity of 25.6 A W^–1 at 0.7 V. For Al/Beet/Cu the calculated zero bias resistance is 23.3 kΩ, which is much smaller than previously reported MIM diodes. For this device f_NL > 3 and f_SENS > 7 A W^–1, so this present device has a great potential as a rectifier. We also proposed a one-dimensional Al/organic semiconductor/Cu diode with low capacitance. The cut-off frequency of the one-dimensional Al/beetroot/Cu device is estimated as 20.8 × 10¹² Hz and if the beet layer is replaced by Cur-M then the estimated frequency becomes 29 × 10¹² Hz. This article also reports the comparative study between a series of natural dyes-based diodes and finally the comparison with our fabricated inorganic Al/TiO₂/Cu diode. The sensitivity of Al/indigo/Cu, Al/turmeric/Cu and Al/beetroot/Cu are 0.4, 4.3 and 25.7 A W^–1 with their zero-bias resistances 2.57 MΩ, 12.8 kΩ and 23.26 kΩ. Again, it was proven by the parabolic behaviour of the dI/dV vs. V plot that all-natural dye-based Schottky diodes may be affected in some way by the quantum tunnelling phenomena. Finally, the simulation was utilized to develop predicted behaviour and a better understanding of the physical mechanisms determining the effectiveness of the device under research.