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

Trap density (Nt), density of carriers (no ) 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 x 10⁹ and 1.8 x 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 kX, which is much smaller than previously reported MIM diodes. For this device fNL [3 and fSENS [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 9 1012 Hz and if the beet layer is replaced by Cur-M then the estimated frequency becomes 29 x 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 MX, 12.8 kX and 23.26 kX. 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. (author)