Co/aniline blue/silicon sandwich hybrid heterojunction for photodiode and low-temperature applications

Abstract

The temperature dependence of the current–voltage and room temperature capacitance–voltage measurements of Co/aniline blue/n-Si sandwich-type rectifying device was investigated.Furthermore, the effects of the illumination on the current–voltage measurements were tested with 100 mW/cm² light intensity, and it was seen that Co/aniline blue/n-Si sandwich-type device showed a clear response to illumination, and it may be a candidate for solar cells or photodiode applications. The rectifying device parameters, such as the barrier height (Ф), the ideality factor (n), the rectification ratio, and the series resistance (R_s), were obtained as a function of temperature using thermionic emission, Cheung function, and Norde function. The interface state densities versus energy were obtained. The Richardson constant (A*) obtained from the In(I_o/T²) versus 1000/T plot was much less than the theoretical value for n-Si. The mean Schottky barrier height $(\overline{\mathrm{Ф}\mathrm{bo})}$ and the standard deviation (σ_o) were calculated using the apparent Schottky barrier height Ф_ap versus 1/2 kT plot. So, it has been found to be 1.08 eV and 0.15 V (260–460 K) and 0.79 eV and 0.10 V (100–260 K), respectively. The results were discussed based on the presence of two Gaussian distributions of Ф_b potential in the contact area of Co/aniline blue/n-Si/Al device.