Current conduction and steady-state photoconductivity in photodiodes with bismuth titanate interlayer

• Current conduction mechanism is modified through BiT interlayer deposition.
• High responsivity and photosensitivity values are obtained thanks to BiT interlayer.
• Al/p-Si with 10 nm BiT interlayer was found suitable for photodiode applications.

Bismuth titanate, Bi4Ti3O12 (BiT), has proven to be a suitable candidate for electro-optical applications, therefore present study aims to report its utility as a photodiode material through current conduction and steady-state photoconductivity investigations. For this purpose, Al/p-Si diodes having thin film BiT interlayer (10 and 25 nm) were fabricated and current-voltage measurements were held in dark and under illumination. Among the samples, better current-voltage characteristics were obtained for the sample with 10 nm BiT interlayer. Deposition of BiT interlayer modified the current conduction mechanism in the forward bias region and interface-limited injection was reported for the diodes with BiT interlayer in the high forward biases. Variation of photocurrent with illumination intensity suggested a supralinear recombination process for the samples with BiT interlayer. High responsivity (2.891 A/W) and photosensitivity (7318.7) values were obtained for the sample with 10 nm BiT interlayer at 250 mW/cm2 illumination intensity. Obtained results suggest that BiT interlayer (10 nm) can be utilized for visible light photodiode and photosensor applications.