Investigation of optical responsivity of BiFeO3-based photodetectors equipped with different electrode patterns

In this study, two different metal electrode patterns are adopted, namely, the straight and curved electrodes, each of which contains 5 different numbers of pairs of interdigitated electrodes. The foregoing design is meant to investigate the resultant photocurrent and dark current magnitudes and the associated hysteresis loops by exposing samples of different numbers of pairs of electrodes to different incident light polarizations. Both linearly and circularly polarized lights are used as incident lights for the measurement of photocurrent. Regardless of its handedness, it is found that the device with curved interdigital electrodes can generate higher photocurrent, vis-à-vis ones with straight interdigitated electrodes. In particular, the device with 8 pairs of curved interdigitated electrodes could have the current enhanced by up to 60%. Finally, among all the photodetectors tested, the highest responsivity of up to 2.15 A/W has also been achieved.