Role of interfacial layer as PANI–silicene in Si-based photodiodes

Silicene is a 2D monoatomic sheet of silicon and can be used for various applications such as degradation, therapy, and biosafety. Polyaniline (PANI) is a conducting polymer employed for electronic devices. In this study, we synthesized PANI–silicene composites and operated as an external interfacial layer between Al and different type substrates of p-Si and n-Si to compare Schottky-type photodiodes of PANI–silicene/n-Si and PANI–silicene/p-Si. The silicene structures were investigated using X-ray diffractometry (XRD) and scanning electron microscopy (SEM) techniques. Also, the light power intensity dependent of PANI–silicene/n-Si and PANI–silicene/p-Si photodiodes carried out in the range 0–100 mW/cm² and I–t measurements utilized to determine the response time of the photodiodes. Basic parameters of devices such as ideality factors barrier, height, and series resistance were obtained by Norde and Cheung methods and thermionic emission (TE) theory from I–V graphs. While the PANI–silicene/n-Si exhibited high ideality factor values of 5.49, the PANI–silicene/p-Si photodiodes showed a low ideality factor of 1.48. The photodiode parameters such as detectivity and responsivity were calculated as 6.40 × 10⁹ Jones and 38.9 mA/W for n-Si substrate and 78.2 mA/W and 8.81 × 10⁹ Jones for p-Si substrate. The case of basic electrical properties for PANI–silicene composite interlayer-based photodiodes was analyzed in detail.