Synthesis of canthaxanthin from β-carotene and evaluation of both substances in diode construction

First, canthaxanthin was synthesized from β-carotene, and it was confirmed by its FTIR spectrum that the synthesized substance was canthaxanthin. Then, three different diodes (Al/β-carotene/n-Si, Al/canthaxanthin/n-Si, and Al/canthaxanthin/p-Si) were made using these substances for interface layer. The current–voltage curves of the diodes were determined both in the dark and under an illumination of 100 mW/cm2 at 300 K. The ideality factors, barrier heights, and series resistances of the diodes in the dark and 300 K were calculated according to Bethe’s thermionic emission (TE) theory, Norde function, and Cheung and Cheung method. Then, the effect of temperature on the current–voltage curves of the diodes was investigated. The ideality factors and barrier heights of the diodes at these temperatures were calculated only according to the TE theory. Finally, the effect of frequency on the capacitance–voltage and conductance-voltage curves of the diodes was investigated.