High Photoresponsive p-Si/n-In2O3 Junction Diodes with Low Ideality Factor Prepared Using Closely Packed Octahedral Structured In2O3 Thin Films

Abstract

Octahedral indium oxide thin films with different precursor concentrations of 0.05, 0.075, 0.1 and 0.125 M were coated on glass substrates at 450 °C using jet nebulizer spray pyrolysis technique. Surface morphology of the prepared samples showed closely packed octahedrons for all concentrations. The measured root-mean-square value of the films was varied between 40.45 and 188.98 nm with increased precursor concentrations. From optical analysis, the calculated optical band gap was continuously decreased with increase in precursor concentrations. A slight blue shift was recorded through the PL spectrum while increasing the precursor concentration due to the oxygen vacancies. The nature of electrical conductivity of the In2O3 films was analysed. Interestingly, we have calculated two types of activation energies in the In2O3 films one is corresponding to low temperature and another is higher temperature. Further, p-Si/n-In2O3 junction diodes are fabricated with different precursor concentrations. Particularly, the 0.075 M of p-Si/n-In2O3 junction diode recorded a minimum ideality factor of n = 2.64 under light exposed condition, confirming the photo-conducting nature of the diodes in visible wavelength range.