Trap-assisted charge conduction mechanism of indigo dye-based organic Schottky diode has been reported in present investigation. Signature of trapping probability has been encountered by G(I–V) vs. V characteristics. Nonmonotonous alignment of aforementioned characteristics emphasizes the existence of trapping states in its charge conduction process. Trap energy (E$_t$) has also been obtained for the device. Estimated value of E$_t$ is 0.073 eV which indicates improved outcome of 16.09 and 3.95%, when compared to other two previously reported organic dyes. Electrical parameters of the device have been estimated by analysing its $I–V$ relationship. Cheung–Cheung method has been used to calculate the series resistance (R$_s$), ideality factor ($n$) and barrier height ($\phi$) of the device. Obtained value of R$_s$, $n$ and $\phi$ are 0.127 k$\Omega$, 39.87 and 0.694 eV, respectively. Analysing the obtained data, Richardson–Schottky effect on charge transport mechanism has been interpreted in this context.

The electrical parameters like barrier height (${\phi}$), series resistance ($R_s$), threshold voltage ($V_{th}$) and trap energy ($E_c$) of a herbal dye-based organic Schottky diode were investigated. Improvement in the outcome of the aforementioned parameters were investigated in the presence of zinc oxide (ZnO) nanoparticles. It has been observed that the preceding characteristics were likewise affected by ZnO nanoparticles. It has been calculated and shown that the incorporation of ZnO nanoparticles lowered the ${\phi}$ of Al/Beet/Cu from 0.75 to 0.73 eV based on I–V characteristics. Analysis of the outcome by using Norde function shows the barrier height reduction from 0.78 to 0.75 eV for the same experiment.Hence, the results produced using two above-mentioned methodologies are in good agreement together. The incorporation of ZnO nanoparticles reduces trap energy and series resistance by 36.98 and 23.81%, respectively, improving currentconduction in the bulk regime and lowering the Schottky diode’s threshold voltage ($V_{th}$) from 0.74 to 0.45 V. The impact of ZnO nanoparticles on a variety of natural dyes, such as turmeric and indigo, has also been studied. Validation of theresults for experimental dyes reveals a wider range of relevance for the current study.