In this study, three different shapes (traditional, spiral, and enclosed) of interdigitated electrodes are designed and implemented on BFO photodetectors (PD). The electrode material used is indium tin oxide or ITO. As the dielectric layer, BFO is sputtered onto the silicon substrate via a radio frequency magnetron sputtering machine and annealed with a furnace tube. Eight experiments are planned according to the procedures set forth by the binary design of experiments (DOE) to optimize the PD fabrication steps. The three process parameters contemplated are annealing gases (nitrogen or oxygen), annealing temperature (300 and 550ºC), and sputtering argon flow rate (5 and 10 sccm). It can be found that regardless of the shape of interdigitated electrodes used, the responsivity and detectivity obtained from Run 3 (annealing temperature of 300ºC, argon flow of 10 sccm, and nitrogen annealing gas) are relatively large. In contrast, the corresponding values are all comparatively small in Run 5 (annealing temperature of 300ºC, argon flow of 5 sccm, and oxygen annealing gas). Furthermore, the interaction between the annealing temperature and the different annealing gases, as well as the argon flow alone, have noticeable influences on the responsivity and detectivity of the BFO photodetectors with the traditional interdigitated and spiral interdigitated electrodes. As for the PDs with the enclosed electrodes, the interaction between the annealing temperature and the different annealing gases also undeniably impacts the resultant responsivity and detectivity.
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.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.